Bizarre Sea Creatures

Bizarre Sea Creatures from Blane Peruns TheSea.Org
Credit: Cédric d’Udekem d’Acoz / Marie Verheye


Are malacostracan crustaceans belonging to the order Amphipoda. They are characterized by having no carapace and having compressed bodies in the lateral plane. There have been over 9,500 species of Amphipoda described, most of them living in the marine environment, with some 1,900 species living in fresh water or on land. The term amphipoda comes from new Latin form with Greek roots of “different” and “foot”, referring to the two types of thoracic legs these animals have.

Amphipoda species have their bodies composed of 13 segments, with major parts grouped into three areas with the head, thorax and abdomen. As with many other crustaceans, the head and thorax are fused into a cephalothorax which carries two pairs of antennae, the mostly concealed mouthparts, and a pair of immobile eyes.

There are many distinctive characteristics between the thorax and the abdomen of amphipods, including the legs, which are different from one part to the other. However, both body parts are laterally compressed, and they are not protected by the characteristic carapace of most crustaceans.
There are eight pairs of legs on the thorax, with the first serving as accessories that aid mouthparts in feeding, with the next four pairs being directed forward and the last 3 backwards. The abdomen of Amphipoda species is composed of two parts, with the pleosome having the swimming legs and the urosome. The urosome is composed of a telson which is forked and of three pairs of uropodes which, in contrast with most other crustacean such as shrimp, do not form a fan-shaped tail.

While most amphipods do not grow to more than 10 millimeters in size, there are documented Amphipoda species which grow to 28 centimeters in length. These specimens have been photographed in the Pacific Ocean at the depth of 5,300 meters. There have been samples assigned to Alicella Gigantea that have reconstructed the total length of the animal to 34 centimeters, with specimens deep within the ocean still to be discovered.

The smallest recorded amphipod is less than 1 millimeter in length. Apparently, the amount of dissolved oxygen in the aquatic environment in which these animals live is the limiting factor in terms of body length that can be reached. For example, amphipods that can be found in Lake Titicaca, 3,800 meters high, grow only to 22 millimeters, while in Lake Baikal, at an altitude of 455 meters, they reach 90 millimeters in length.

Arctic Hydromedusa

Arctic Hydromedusa Bizarre Sea Creatures
Credit: NOAA

The Arctic Hydromedusa has been only recently discovered. The creature lives in the cold waters of the Arctic Ocean, especially around North Canada and Greenland, often as deep as 3,300 feet – no wonder that scientists had the chance to meet and research the spectacular critter only after robotic submarines reached the dark depth. Also named Bathykorus bouilloni, this new jelly species is a genus of its own – the animal stands alone in its class and still subjected to ongoing research.

The Arctic Hydromedusa is a very small critter – the diameter of its gelatinous, pale-blue body reaches only 2 cm. The body features four long, solid tentacles that are not contractile and are positioned high around the dome and four other, shorter tentacles positioned lower, around the undulating margin of the domed body. The animal uses the long tentacles for orientation, always holding them in the direction of the movement. The circular mouth positioned centrally on the body is connected to the gastric chamber with a dozen of gastric chambers.

The best way to study creatures of the sea is in the laboratory, but the Arctic Hydromedusa is a very sensitive and fragile creature and most attempts to capture it alive have failed. This sensitivity leaves scientists only one choice: they observe the creature in its natural habitat, through remotely operated underwater vehicles. They are also constantly trying to come up with new methods to capture specimens alive, and gentle suction seems to have yielded some success already.

Armored Snail

Armored Snail Bizarre Sea Creatures
Credit: David Shale

The Armored Snail, also known as the Scaly-foot Snail or the Sea Pangolin or Chrysomallon squamiferum, is one of the species of the deep seas that are endangered because of deep-sea mining. The snail thrives in waters that are rich in minerals, especially in pyrite and iron sulfide, substances that are absorbed into the snail’s shell, strengthening it and giving it its golden color and armor-like appearance. The iron sulfide is also absorbed in the body of the animal and forms the small iron plates that cover the snail’s foot.

The Armored Snail has developed its shell to provide it with protection from all enemies. The shell consists of three layers: a golden outer layer that contains the iron sulfide, a middle layer that consists of softer, organic material and an innermost layer that consists of a form of calcium carbonate called aragonite. The outer layer is there to provide the strength of the armor, the softer layer in the middle absorbs any shock that the owner suffers, while the calcified layer is also there for added strength.

The creature inhabits the waters around hydrothermal vent fields around Mauritius and on the Central and Southwest Indian Ridge, the depth it prefers being around 1.73 miles (2,780 meters), on a territory of only 0.27 square kilometers. The species has been discovered in 2001, around the Kairei vent field through which the water rich in minerals is squirted from underneath the seabed at an incredible 750 Fahrenheit.


Barnacles Bizarre Sea Creatures
Credit: Justin Bajema

Barnacles are arthropods belonging to the infraclass Cirripedia of the subphylum Crustacea. They are closely related to similar crustaceans such as crabs and lobsters. Barnacle species are exclusively marine and they live attached to surfaces. Cirripedia comes from Latin, and translates into curl-footed.

There are over 1,200 described species of barnacle, living mostly in shallow marine waters. They attach themselves permanently unto hard surfaces after which they encrust themselves. The common acorn barnacle is sessile, attaching itself unto various hard surfaces, building a shell unto the substrate, while the goose barnacle and many other species use a stalk in order to attach themselves.
While some barnacles have been found to live as deep as 600 meters below sea level, most of them prefer shallow waters of less than 100 meters, with some other species living in intertidal zones. Because intertidal zones have periodical desiccations, most barnacle species living in this area are well adapted against water loss. They have calcite shells that are impermeable, and they also possess two plates they can slide to enclose themselves while they are not feeding. These plates also serve to protect these animals from various forms of predation.

Most barnacle species are suspension feeders. They attach themselves permanently unto a surface, encrust themselves with a shell composed of six plates, and when feeding, they extend their cirri, or feathery legs which they rhythmically beat in order to draw in water along with plankton and detritus into their shell for feeding. However, there are other barnacles that live as parasites. For example, members of the genus Sacculina are parasitic to crabs, living within them.

Most barnacle species are displaced by mussels and limpets in the competition for space. Besides competition, there are also many predators that feed on barnacle species, and the latter have developed several mechanisms to overwhelm both their competitors and predators. The first strategy is swamping, which means that the barnacle species overcomes competition by covering an entire area with individuals, allowing some of them to survive.

Fast growth is another employed strategy that allows them to grow and reach higher areas in the water column that are unreachable by their competitors. Not only that, but the fast growth also allows them to become large enough so as to be difficult or impossible to be displaced by limpets and mussels. Some barnacles such as Megabalanus may grow to 7 centimeters in length.

Bearded Fireworm

Bearded Fireworm Bizarre Sea Creatures
Credit: Alfonso González

The bearded fireworm is a member of the bristleworm family. Bristleworms all look hairy and many of them are venomous, but this extraordinary species is even hairier than most of its relatives and it was named fireworm after the intense burning sensation it causes with the toxins it releases through its hairs.

Fireworms are quite common in the Mediterranean and in the Caribbean region, and the coastal areas of the Atlantic Ocean also give home to many of these worms. They love warm, shallow waters – therefore, they are found mostly in reef areas, in waters not deeper than 40 m.

Bearded fireworms are quite large, usually between 15 and 30 cm long. They have a flattened and elongated body divided into numerous separate segments, usually 60-150 of them, gills located on the sides, a ventral mouth on the second segment and a head on the first one, with the sensory organs such as the eyes. The hair-like bristles are quite long and they are arranged in clusters on the sides of the body, each bundle being rooted in an organ called parapodia, which is also used for locomotion and breathing. The hairs are hollow inside; therefore, they are quite sensitive and break easily, but they are also the animal’s main weapon used for injecting a venomous chemical into its predator.

Fireworms are varied in terms of coloring – they are actually quite spectacular. Green, red, yellowish and brown fireworms are just as common as white ones. Many individuals are multicolored, with the segments being of one color and the bristles of a different color.

These fireworms are voracious and aggressive. The usually prey on small crustaceans, the polyps of stony corals – Gorgonian corals are their favorites – and anemones, and they also feed on dead animal particles floating in the water. When a fireworm finds a suitably appetizing coral, it climbs to the tip of the branch and takes it in its mouth, wrapping itself around the branch. The worm moves on only when it has sucked all life out of the branch.

Being slow-moving creatures, they have developed a very efficient defense mechanism: they protect themselves by stinging their predators. The long bristles puncture the skin of their enemies and inject a neurotoxin into them to cause a painful, burning feeling, repelling enemies. The bristles can penetrate the human skin, too, causing dizziness, nausea and the burning sensation on the skin where it came into contact with the worm. However, they do not attack deliberately, the bristles flare only when the animal is touched.

Bearded fireworms put on a real show during mating. The females come to the surface of the water and start emitting a fluorescent glow to attract the males. The males respond to the glow by emitting flashing light signals, then they approach the female. Fertilization happens externally -the females release their eggs and the males their sperm into the water, the two types of cells combining to give life to young bearded fireworm individuals.

Benthic Comb Jelly

Benthic Comb Jelly Bizarre Sea Creatures
Credit: NOAA

The benthic comb jelly, a new member of the genus called Aulacoctena, was first seen in 2002, at the bottom of the Ryukyu Trench, in the deep waters off the coast of Japan. The creature was discovered by a robotic vehicle at the depth of over seven thousand meters and is considered to be the deepest dwelling comb jelly species known today.

The gelatinous body of the benthic comb jelly measures 5-8 cm in width and it is 10-20 cm long. It has two long filaments with which the animal can attach itself to the sea floor and two other, retractable tentacles.

The discovery of this new comb jelly species raises lots of questions. It was previously thought that actively hunting predators, such as the comb jelly, could not survive in such deep water because the environment does not have any food sources for them. However, this new-found comb jelly species does thrive on the macroscopic food sources captured through active hunting, which means that scientists need to carry out further research of deep-sea environments. Such deep waters are currently inaccessible for humans, but the already very advanced technologies used for observing benthic life are in continuous development, so hopefully we will soon know much more about the special, hardy creatures of the deepest spots on Earth. The process is likely to reveal more new species and will allow for a better understanding of deep-sea ecosystems as well.

Bioluminescent Octopus

Bioluminescent Octopus Bizarre Sea Creatures
Credit: ORCA

The bioluminescent octopus (also known as Stauroteuthis syrtensis) is mostly found in the North Atlantic Ocean, in depth between 500 m and 4,000 m, its favorite range being between 1,500 – 2,500 m. The animal is among the most beautiful and most fascinating creatures of the deep sea and certainly one that scientists still have plenty to find out about.

The marine animal is small, measuring only about 10 cm in length and about 4 cm in width, but its reddish-brown body is surrounded by eight long tentacles that make the critter look much larger. Each of the animal’s tentacles is lined with 60 adhesive suckers and 40 modified, light-emitting suckers.

The feature that distinguishes this octopus species is the presence of the 40 distinct photophores, glandular organs that line the tentacles and are capable of producing a characteristic blue-green light. Some specimens emit a continuous, faint light, while in others the photophores are active for only about 5 minutes following a stimulating event. Scientists believe that the light emitted has a double purpose: it drives away predators and it attracts food (the primary diet of the bioluminescent octopus consists of tiny crustaceans, efficiently lured by the light). For a while, scientists thought that the light emitted also has the role of sexual signaling, but the theory was dismissed after they discovered that light of the same type, color and intensity is emitted by both sexes, by fully-grown and immature specimen alike.

Black Swallower

Black Swallower Bizarre Sea Creatures
Credit: Pinterest

The black swallower (known under the scientific name of Chiasmodon niger) is one of the most bizarre inhabitants of the deep seas. Dwelling in the subtropical waters of the south-western and northern Atlantic Ocean, usually found at the depth of around 2,7 km, the species has received its name from its extreme appetite and its color.

When its belly is not stuffed full, the black swallower’s body is slender and around 25 cm in length. However, the ability to eat up other creatures without taking smaller bites at the prey is noticeable at once: black swallowers have a very wide mouth, with the jaws as well as the palate covered in teeth, some hooked, others straight, but all of them razor-sharp. The prey swallowed passes through the mouth into the special gut that extends to hang underneath the body to hold the devoured animal.

The black swallower is able to swallow prey that is twice its length and 10 times its weight and it is exactly this voracity that often leads to its death. The purpose of ingesting large quantities of food in one piece is to have nutrients to live on for a while, but when the fish swallowed is too large, the gut cannot digest it completely before the matter starts decomposing. The process generates gastric gases that cause the excessive inflation of the gut and the subsequent bursting of the gut that inevitably leads to the animal’s death.

Blob Sculpins

Blob Sculpins / Blobfish Bizarre Sea Creatures
Credit: NOAA

Blob sculpins, also known as blob fish, are perhaps the strangest-looking creatures of the marine world. These strange animals live in the deepest waters of the sea, so it is very unlikely for hobby divers and snorkeling enthusiasts to come into contact with them, but, nevertheless, they are among the most peculiar creatures that have ever dwelled the salty waters.

Blob fish live mainly in the deep waters of the Pacific Ocean, in the area stretching from Southern California to the Bering Sea, but there are a few individuals living around Australia, New Zealand and Tasmania as well. They are mostly found at depths between 600 – 2,800 m, but it is believed that they inhabit much deeper waters as well.

Blob fish live in an unfriendly environment of almost complete darkness, where water temperature never rises above 10 degrees C (50 F) and pressure is unbearable for humans and for most animals as well. Given these harsh circumstances, the body of the blob fish is structured in a way to be able to endure the conditions of the world around. Its body is of very low density, which makes it look completely different when it is in its natural environment and is under the pressure of the water and when it is out of the water and decompressed. There is not a single muscle in its entire body and no bone either, which also increases its capacity to live in a high-pressure environment, but makes them unable to swim.

The blob fish has been repeatedly voted the ugliest animal on Earth and, indeed, when it is out of the water, it looks like a mass of jelly, with small eyes, a large, unsightly nose and loose skin. Though it has been very rarely observed in its natural environment, it is believed that the blob sculpin is quite fish-shaped down under, with a large head and large lips, a flattened tail and grayish skin that is covered in scales ending in small spikes.

The blob fish has no gas bladder – it would not resist the special conditions. It stays buoyant because its body’s density is similar to the density of the water. They are relatively large, usually about 70 cm long, the largest individuals reaching the weight of almost 10 kg.

Bobbit Worm

Bobbit Worm Bizarre Sea Creatures
Credit: Rickard Zerpe

The bobbit worm, scientifically known as Eunice aphroditois is a bristle worm species living in the Atlantic Ocean and in some areas of the Indo-Pacific Ocean, in burrows dug into the ocean floor. The creature prefers warmer waters and it likes prowling coral reefs, where nutrients are plentiful.

The body of bobbit worms can range from only 10 cm to 299 cm, but they are very thin, measuring only about 1 inch across the back. Its entire body is covered in the exoskeleton. The head of the worm has two eyes as well as five antennae used as sensors to identify prey. The mandibles of the worm are strong, capable of snapping smaller prey into half. Bobbit worms feed by snapping and taking their prey into their burrows – the voracious animal does this very quickly, being able to capture the prey and to retract into the hole at a speed of around 20 feet per second. The creature’s bite is so strong and its appetite so big that it often causes damage to the individual coral that gives home to bobbit worms.

Not many predators dare to mess with the bobbit. The ones that do need to attack it in groups, swimming into the worm’s hole and spitting water into its face from up close. The spitting freezes the worm for a short time, but if the attackers are not quick enough to kill the worm while it is stunned, the bobbit will strike back, biting and injecting toxins into the body of the fish.

Carnivorous Harp Sponge

Carnivorous Harp Sponge Bizarre Sea Creatures
Credit: Monterey Bay Aquarium Research Institute

One of the newly discovered wonders of the ocean, the carnivorous harp sponge is a unique species of deep ocean sponge discovered off the shore of California at a depth of more than 3,000 meters. Chondrocladia lyra – in its official designation – was named the “harp” sponge due to its unique harp-like shape. It was found to be quite different from most other species of sponges, due mainly to its less common feeding habits.

The carnivorous harp sponge is a sessile organism that was discovered in 2012 and, soon enough, became extremely popular, being listed among the top new discovered species in 2013. Boasting a highly unique, candelabra-like structure, the sponge is actually able to capture other sizable sea creatures in a unique and distinctive fashion, exposing it to ocean currents, so that it would have a better chance at catching its prey. Through its distinctive shape and development, as well as its uncommon feeding habits, the harp sponge quickly became the center of attention as scientists continue to uncover its many secrets.

The harp sponge has a body that resembles a lyre or harp, featuring one to six equidistant connections between its vertical branches. The sponge is able to anchor itself into the sea floor at extreme depths of up to 3,500 meters using a rhizoid structure shaped like a plant’s root. Covered by hooks and spines, the harp like branches have the role of acting as a net and capturing the carnivorous harp sponge’s prey with greater ease, as it is carried by deep ocean currents. Although most carnivorous harp sponges are quite small in size, the largest specimens ever discovered can actually reach up to 60 centimeters in length.

The feeding habits of the harp sponge is definitely one of its most distinctive features, mainly due to the contrast between its carnivorous development and that of other sponge species. The fact that most sponges are suspension feeders and feed mostly on the tiniest organisms, such as bacteria and other microscopic creatures, has been known for years. The carnivorous harp sponge, however, is something completely different. It feeds on larger prey, such as various copepods, using its unique hooks to capture its prey. Once it has done that, the sponge secretes a digestive membrane, somewhat like a cocoon, that slowly breaks down the captured prey, and turns it into vital nourishment that is then absorbed through the pores of the sponge.

It has already been discovered that the sponge is able to thrive in the extreme, unforgiving conditions of the deep ocean – at depths greater than 3,000 meters. But the species itself may be far more prevalent than it was first thought. Aside from the specimens discovered near the coast of California, C. lyra is also believed to dwell in other areas in the northeast Pacific, up to 1,600 km away from the Escanaba Ridge, where it was first spotted. Resilient and adaptable, the carnivorous harp sponge still likely has many secrets to share, as scientists are only just beginning to discover its many unique qualities.

Colossal Squid

Colossal Squid Bizarre Sea Creatures
Credit: John Bennett

The colossal squid is, like the name suggests, colossal, indeed, in terms of the size of its habitat as well as in terms of body size. The creature inhabiting the wide territory that stretches from the Antarctica, through the waters that surround South America and South Africa, all the way to New Zealand, in waters the depth of which ranges up to 2.2 km, is the largest known squid on Earth. Known under the scientific name Mesonychoteuthis hamiltoni, this huge squid can grow to the size of 12-14 meters in length and can reach the weight of 750 kg, making it the largest invertebrate known today.
The critter’s truly colossal limbs are not only long and strong – they are also lined with toothed suckers and sharp hooks that are either three-pointed or swiveling.

The creature’s huge body moves very slowly, so it is more an ambush predator than an active hunter. This feature accounts for the extra-large eyes as well – it needs to be able to see very well to be able to spot the prey and to move its long limbs with precision to capture the food consisting mainly of toothfish as well as of other smaller fish.

One of the dead specimens found had eyes that measured 27 cm in diameter, with a pupil of 9 cm. According to scientific estimations, the eyes were even larger when the animal was still alive, possibly around 30 cm in diameter.

Crossota Norvegica Jellyfish

Crossota Norvegica Jellyfish Bizarre Sea Creatures
Credit: Kevin Raskoff

An inhabitant of the deep waters of the Arctic Ocean, the tiny deep-red jellyfish, mostly known by its Latin name, the Crossota Norvegica jellyfish stuns with its appearance. Found at depths of around 1 km, where the temperature stays in the 3.7 – 3.9 degrees Celsius range, but first spotted much deeper, at around 2,600 meters, the small red creature grows to only 2 cm in diameter, but its body is very complex. While other hydromedusae have only 8 radial canals, the Crossota Norvegica has 10-14, and it also has 5-7 strangely upturned lips.

The complex body of the small hydrozoan, however, comes with an incomplete development: while other members of the glass spend only a short while in the planktonic stage and then they pass into the sessile stage, when they attach themselves to the substrate, this jellyfish stays in the planktonic phase and never becomes sessile.

The creature is mysterious in many ways – nobody knows what the Crossota Norvegica feeds on. As other species in the class feed on zooplanktons that they avail themselves to with the help of their tentacles, scientists suppose that this tiny jellyfish thrives on planktons, too, but no evidence of the process has been found yet.

The blood-red little critter was discovered with the help of advanced deep-sea technology, when the scientists of a two-month long NOAA (National Oceanic and Atmospheric Administration) expedition sent an unmanned vehicle into the deepest, most mysterious waters of the Canadian Basin.


Cumaceans Bizarre Sea Creatures
Credit; Wikimedia Commons

Cumacea is an order within the superorder Peracarida, and it comprises of small crustaceans that live in the marine environment. These crustaceans are also called comma shrimp or hooded shrimps for their distinct body shape and plan. They usually live on soft substrates on the bottom of the sea.

The body of cumaceans is well protected by hard shells, with an enlarged carapace protecting the head and the pereon protecting the first part of the abdomen. These animals also possess a slim abdomen and a tail that is forked at the end. The shape of their body with the curved tail is what brought them the name comma shrimp. Most species are small in size, with most of them ranging from 1 millimeter to no more than 10 millimeters.

The head piece of Cumacea species is usually composed of dorsal head parts that are fused together along with the thorax and the first three somites into a single carapace. Within this carapace can be found the appendages used for respiration and for feeding. Most cumaceans have two eyes situated on the dorsal side, with some species having them merged into a singular eye lobe. The pereon is formed from the last 5 somites of the thorax while the pleon, or elongated abdomen is composed of six somites of cylindrical shape.

Most Cumacea species live in the marine environment. While many species require higher salinity levels in order to survive, there are some that can live in brackish water with lower salinity. There are some cumaceans in the Caspian Sea that even go upsteam rivers that flow into it, with other species able to live in intertidal zones.

The average life span of cumaceans is one year or less, and they manage to reproduce twice over the course of their lifetimes. The species that live at deeper sea levels have a slower metabolism and thus have an increased longevity. Cumaceans live on the sea floor in muddy or sandy substrates and feed on organic material or microorganisms within them. Some species filter water along with food, others go for singular grains of sand, while some cumaceans have specialized mandibles that form piercing organs with which they prey on small crustaceans and foraminiferans.

Cuvier’s Beaked Whale

Cuvier’s Beaked Whale Bizarre Sea Creatures
Credit: Tethys

The Cuvier’s beaked whale, also known as the goose-beaked whale or Ziphius cavirostris in Latin, is the most widely distributed beak whale on Earth, equally found in the Mediterranean, in the North Atlantic and the North Pacific, around South Africa and New Zealand. Cuvier’s is also the most frequently seen whale species, even though its preferred habitat is deep down, at around 1,000 meters.

Named after the scientist who first described it in the 19th century, French anatomist Georges Cuvier, this widespread whale species grows quite large, its robust, strong, cigar-shaped body reaching 5-7 m in length and with many specimens weighing around two and a half tons. Though it is a beaked whale, the beak is much smaller than in other beaked species. The small beak has a somewhat upturned jawline, creating the illusion that the animal is smiling all the time.

The Cuvier’s beaked whale is a hunter, its diet consisting mainly of small fish and squids.
Whales regularly dive, then they resurface to inhale and to exhale. The time they usually spend submerged in the water is usually not very long, but the Cuvier’s beaked whale is an exception: in 2011, a Cuvier’s whale tagged by scientists for tracking dove to the depth of almost 3,000 meters and spent there two hours and 17 minutes before returning to the surface again. The dive is considered to be longest and deepest one ever recorded since mammals started to be observed.

Deep Sea Anglerfish

Deep Sea Anglerfish Bizarre Sea Creatures
Credit: Kirsten and Joachim Jakobsen

The deepest depths of the ocean are filled with strange creatures that have adapted in the most diverse and unusual ways to cope with the cold, high pressure and darkness of the bottom of the ocean. Deep sea anglerfish are predators that have evolved to survive quite successfully in these harsh environments, while also being seen as one of the weirdest species of anglerfish found in the entire ocean.

Deep sea anglerfish are among the most unusual and feared predators of the deep ocean, often known to roam the bottom of the sea at depths of several thousand meters. There are several species of deep angler fish, some of which have specimens that can grow up to 1 meter in length, or even more. Their characteristic large jaws, sharp teeth and – in some cases, a luminous organ that helps them hunt for prey – are the most well-known features of this unique species of fish.

The esca – the luminous organ extending from the top of their heads – is one of the most distinctive features of the deep sea anglerfish. Worn by females, this organ is capable of producing light through an – as of yet, largely unknown – method based on bacterial growth. Scientists suspect that bacteria enter the esca through small pores and multiply within it, until their numbers are great enough to produce the light that the anglerfish needs in order to hunt. This “stylish” feature also helps the females of the species to attract mates more easily.

Deep sea anglerfish have one of the strangest and – in some ways disturbing – reproductive cycles. The males of the species are known to roam the bottom of the ocean in search of viable females, only to then latch onto them with their teeth and gradually become parasites whose organs slowly become symbiotic with those of the female. A single female can often take several males into its body, physically fusing with them until the male parasites become physically dependent on the female host for their own survival. This strange symbiotic relationship is actually extremely important for the species’ survival due to the extreme difficulty associated with finding a viable mate in the depths of the ocean and the dependence that females have on having a mate close by as soon as they spawn. Also, it’s important to note that not all species of deep sea anglerfish rely on male parasitism and, in some cases, the male is the one most well-equipped to find viable prey.

Anglerfish are opportunistic, low energy consumers that thrive in the depths of the abyss and the bathypelagic zone. The esca plays a major role in their ability to attract prey, while their large, fearful mouths and teeth close with extreme speed, often around whole fish, without the need to tear their prey into pieces before being able to eat it. In fact, their flexible and adaptable bodies allow them to sometimes eat fish even twice their own size. The deep sea anglerfish is able to produce significant amount of light through the esca and use it to attract prey such as pandalid shrimp and various types of crustaceans. Scientists have observed deep sea anglerfish to have adapted to become highly energy-efficient, so that they can linger for a long time at the bottom of the ocean without having to feed.

Diving Bell Spider

Diving Bell Spider Bizarre Sea Creatures
Credit: Smithsonian

The diving bell spider (Argyroneta aquatica) is the only known species of spider that spends almost all its life in water and is a genus of its own as well. The spider’s size ranges from 7.8 – 13.1 mm and it eats, catches its prey, mates and lays eggs in the water, coming to the surface only for breathing once a day.

The diving spider can be found in freshwater environments where aquatic vegetation is plentiful, such as lakes, ponds and marshes. The animal’s habitat ranges through almost all of mainland Europe, the northern part of the Asian continent. The species received its name from the shape of the webs built by these spiders to serve as a tool to capture prey as well as for mating and laying eggs (purposes served only by the webs built by females). The bells are built from a material made from waterproof silk that allow for gas exchange, but not the penetration of water into the spider home and a hydrogel that scientists have not yet determined. They are built between the submerged parts of aquatic plants and are filled with air bubbles that the dwellers take rising to the surface.

The diving spider’s bite is not dangerous for humans, but it is particularly painful. The small animal has very thin and sharp fangs that can pierce through human skin and leave behind a painful, swallowed bite mark. The animal’s bite can cause local inflammation and fever.

Dumbo Octopus

Dumbo Octopus Bizarre Sea Creatures
Credit: Schmidt Ocean

Considered by many to be the cutest octopus, the Dumbo octopus has received its name from the fins that look like elephant ears and which confer this little creature a very characteristic appearance. The fins have an essential role in the animal’s life: the octopus uses them for stability while it is propelling itself forward with the help of the water pushed through their siphon.

The genus of Dumbo octopuses, Grimpoteuthis, comprises 13 distinct species, all of them umbrella octopuses. Despite the fact that the habitat of the Dumbo octopus is very wide, it is very rarely seen and scientists believe that they are among the rarest octopuses on Earth. The animal prefers the deepest waters, it lives at depths of at least 4,000 meters, but some of them might live even at 7,000 meters.
The Dumbo octopus is a small animal. Its body usually reaches only the length of 20-30 cm, though the largest individual ever found was 1.8 m long (and it weighed around 6 kg).

Female Dumbos simultaneously carry eggs in different stages of maturation. The mating period is probably determined by environmental factors and can take place any time when the conditions are favourable. The egg-laying behaviour of female Dumbos is strange, too: they either lay their eggs under rocks or they carry the eggs around under or on their arms. The young ones are able to eat and to defend themselves right after they are born, therefore the mother does not spend any time with them after they hatch.

Fangtooth Fish

Fangtooth Fish Bizarre Sea Creatures
Credit: Solvin Zankl

The fangtooth is a small and completely harmless critter of the deep seas, but its scary face makes it look like a creature from a horror movie – the scientific name of the animal’s genus is Anoplogastridae, a word of Greek origins that means something like “unarmed stomach”. The genus comprises two known species, the shorthorn and the common fangtooth.

These fanged fish live in the deep waters of the Atlantic and the Pacific, at depths ranging between 200 and 2,000 meters. While fully-grown individuals prefer the deeper waters, younger ones usually stay in the upper range. Both species feed on the planktons that they filter out of the water, but the adults that live in the deeper layers are known to be predators that feed on small squids and fish.

The two species of the genus share most features – they both have large heads and disproportionately long, fang-like teeth, eyes that are small and positioned high on the head, small, spineless fins and scales that are deeply embedded in the skin and are shaped like small plates.

The shorthorn fangtooth is the larger species of the two, reaching the size of around 16 cm, while the other species is half that size. The teeth that create the characteristic appearance in both of them are the largest that can be found in the world of fish when calculating their proportion to the size of the body.

Frilled Shark

Frilled Shark Bizarre Sea Creatures
Credit: Wikimedia Commons

The frilled shark (Chlamydoselachus anguineus) is a large and able-bodied inhabitant of the Pacific and the Atlantic oceans that prefers waters the depth of which is around 1,200 meters, but in some areas they might dive much deeper, to over 1,500 meters, or ascend to around 20 meters under the surface.

Often termed a living fossil and likened to mythical creatures, the frilled shark features a body retains several primitive features. Its body is dark-colored, almost black, very flexible and eel-like, with dorsal, anal and pelvic fins positioned close to the tail. The animal has six gill slits, out of which two meet under the throat and all of which look as if they were frilled – hence the name. The nose is very short, with vertical nostrils, while the head is rounded, with large eyes that have third eyelids for more protection. The jaws are very long and lined with sharp and widely-spaced teeth – 19-28 of them in the upper jaw and 21-29 in the lower jaw.

When capturing prey, the frilled shark makes maximum use of its flexibility: when it catches sight of the prey, first it bends its body, then it lunges forward, in a motion that is more typical of snakes. The long jaws are also very flexible, allowing the shark to open its mouth wide and to capture and swallow fish that are half its body size. The staple diet of the creature consists mainly of cephalopods and bony fish, but occasionally it might attack other sharks as well.

Giant Isopod

Giant Isopod Bizarre Sea Creatures
Credit: Hiroyuki Terada

The giant isopod (Bathynomus giganteus) is a huge crustacean that lives in the cold, deep waters of the Pacific, the Atlantic and the Indian Oceans, usually between the depths of 170 m and 300 m and the creature that is considered to be the largest isopod on Earth – typically, they reach the length of 7.5-14.2 inches, but individuals that reached the length of 2.5 feet have also been found. Their maximum weight is around 1.7 kg.

The giant isopod is an impressive critter in terms of appearance as well. Its body is quite flat and it is protected with a thick and resistant exoskeleton that has overlapping segments. The exoskeleton is flexible as well, so much so that it permits the animal to curl into a ball when it senses danger. The critter’s eyes are large and very complex, consisting of 4,000 facets. The head also has two pair of antennae.
Giant isopods are generally benthic scavengers, preferring waters that are cold, but what they like the most is meat, so they often feed on dead sharks, fish or squid and they may also hunt actively to catch slow-moving prey, such as sponges or sea cucumbers.

Though these creatures love to eat and when they do, they consume huge quantities of food, they can resist for a very long time without grabbing a bite – an individual in Japan had stayed alive for five years without eating anything and many of them eat only once or twice a year.

Giant Oarfish

Giant Oarfish Bizarre Sea Creatures
Credit: CIMI

The giant oarfish (Regalecus glesne) is a large-bodied member of the oarfish family, the longest bony fish known today and also one that lives so deep in the coldest waters of the ocean that scientists rarely have the chance to observe it (most of the individuals that have been observed were either severely injured or dead). It is a large, but very shy creature and it is believed to be very rare, too.

The creature’s name refers to the shape of its body – the elongated, ribbon-like body is narrow, it has a single dorsal fin and oar-shaped fins on the animal’s pelvis. The thin body is very flexible and it allows the animal to move in a serpent-like fashion. The term giant also refers to the animal’s body – adult individuals can reach the length of up to 3 m and they can weigh up to 270 kg, but several specimen measuring up to 7 m in length have also been found.

As for the longevity and the reproduction of the giant oarfish, scientists can only speculate and deduce their behavior from other, more known oarfish species. It is thought that the creature reproduces by spawning between July and December, with the eggs floating close to the surface for about 3 weeks before hatching.

This oarfish species is particularly choosy when it comes to food, one reason for the pickiness being the complete lack of teeth. The animal’s jaws have 40-58 gill rakers that are suitable for capturing only small organisms, therefore the diet of the giant oarfish consists mainly of small squids, shrimps, tiny fish and crustaceans.

Giant Siphonophore

Giant Siphonophore Bizarre Sea Creatures
Credit: Monterey Bay Aquarium Research Institute

The giant siphonophore, or Praya dubia, is a deep-sea invertebrate of the North Atlantic Ocean, living at depths between 700 and 1,100 meters, but it has also been found in coastal areas from Iceland to Chile.
The critter thrives mainly on tiny prey that it attracts with the help of bioluminescence, the ability to emit light underwater. The bright blue light, however, is not the only tool that helps the giant siphonophore feed – when it finds its way to an area where food is plentiful, it extends its numerous tentacles lined with nematocysts that release a very powerful toxin that kills the prey that comes into contact with it. The giant siphonophore’s diet consists mainly of gelatinous organisms, such as the larvae released by fish and it is known to eat tiny fish as well. The toxins released by the siphonophore plays a protective role as well – the creature has no known predators.

This strange creature is very thin and long. Its body length can reach 50 m and a thickness similar to an ordinary broomstick, which makes it the second longest sea organism (the first one is the bootlace warm). The chain-like shape is due to the fact that giant siphonophore is, in fact, not a single organism, but a collection of zooids, tiny components that could not live on their own otherwise and all of which have a specific function – some have a role in stabilizing the creature’s body, others in moving, feeding or in reproduction.

Goblin Shark

Goblin Shark Bizarre Sea Creatures
Credit: NatGeo

The goblin shark (Mitsukurina owstoni) is often called a living fossil. Coming from a lineage that is around 125 million years old and being the only still existing member of its family, this shark looks like an ancient, mythical creature, indeed – its pink body, its long, flat snout, its protruding jaws lined with sharp teeth, make it resemble a goblin, or a Japanese demon. The animal is also quite large – adult individuals usually are about 10 feet long, but much larger specimens have also been found, some of them almost 13 feet long and weighing over 460 pounds.

The habitat where most goblin sharks live is in the deep waters of the Pacific, the Atlantic and the Indian Oceans, usually in the depth of 900-4,300 feet (though young ones like to stay higher up and are usually found at around 90 feet underneath the sea surface). The shark is the most common around the coasts of Japan and that is where it was first found by local fishermen. The goblin shark feeds mainly on bony fish, crustaceans and squid, but shrimps, fin rays and octopuses are also delicious treats for them.

The shark’s jaws are tied together by very flexible ligaments that allow them to move forward very quickly when the prey comes close enough to be captured. The strange construction of the mouth allows the animal to catapult it forward completely, to a distance of about 9% of its body length.

Golden Lace Nudibranch

Golden Lace Nudibranch Bizarre Sea Creatures
Credit: David Fleetham

The golden-lace nudribranch (Halgerda terramtuentis) is a beautiful sea mollusk endemic to the waters around Hawaii. The creature is golden, indeed – its translucent body is of a soft, pale yellow hue and it is adorned with yellow and orange lines that create an irregular, web-like pattern. The body is not smooth – it has small tubercles, that is, tiny bumps which are of a lighter color, creating the illusion of a glow. The body is embellished with other ornaments as well – it has a white, tree-like structure with black spots on one side that is practically the animal’s gill.

This beautiful dweller of the sea prefers the shallow waters. They are usually found in waters that are less than 10 meters deep, where they live hiding in small caves and under rocks. Most golden-lace nudibranch individuals are small (most of them are less than 5 cm in length when fully grown), but that does not stop them from hunting – these carnivorous little critters don’t bite, but they are known to hunt for sponges and other soft critters.

This nudibranch was discovered in 1982 by two researchers of Hawaii University, Hans Bertsch and Scott Johnson. Though species are usually named after the person who discovered them, the word “terramutentis” in the name is not the name of its discoverer – it means “looking at the earth with care” and it was chosen to honor the Earthwatch, the group of volunteers who helped the two researchers with their work.

Gulper Eel

Gulper Eel Bizarre Sea Creatures
Credit: Monterey Bay Aquarium Research Institute

The gulper eel, also known as the pelican eel or Eurypharynx pelecanoides, is a dweller of the deep layers of the North Atlantic, usually found at depths ranging between 500 m and 3,000 m. The creature received its name because of its mouth, which is larger than the animal’s body and looks and functions in a way very similar to that of the pelican’s. The animal is not very large – adult individuals reach only the length of 70 cm.

The body of the animal resembles that of the eel, but the creature is not an eel, in fact – it is a ray-finned fish. There are several physical features that betray its true identity – it doesn’t have swim bladders, pelvic fins and scales. The gulper eel’s eyes are also different from other deep-sea creatures – they are much smaller.

The diet of the gulper eel consists mainly of small crustaceans. They have quite an appetite – their stomach is very flexible and it can stretch to accommodate large amounts of food. The large jaws, that take up about 25% of the animal’s total body length, serve efficient eating, but they are lined with very small teeth that do not make it possible to crab larger bites.

The creature’s tail plays an important role in movement as well as in capturing prey. The animal uses the tail to propel itself forward and the tail also emits a pink glow or red, flashing light to attract prey.

Hair Jelly

Hair Jelly Bizarre Sea Creatures
Credit: Alexander Semenov

Cyanea capillata, also known as hair jelly or lion’s mane jelly fish, is the largest species of jelly fish known today. These stunningly beautiful creatures are colorful and really large – the largest individuals seen measure 120 feet in length when the tentacles are fully extended.

They prefer cold water marine habitats, being common and widespread around the Arctic, in the North Sea, in the seas around Scandinavia and in the Irish Sea. They usually live in the shallow waters, floating and swimming around in waters not deeper than 20 m. They sometimes migrate over large distances – they propel themselves with slow, pulsating movements and they also use the water currents to make traveling easier for them.

Lion’s mane jelly fish are large, but only few of them reach the record length mentioned above. The individuals that live in the north usually have larger bodies than their counterparts inhabiting lower latitudes and their tentacles are also longer, usually reaching the length of 100 feet. Independent of their size, all lion’s mane jelly fishes have eight clusters of colorful tentacles, the bundles containing a huge number of individual arms, usually more than 100 each. The tentacles start from the center of the body called the bell that is divided into eight separate lobes. It is the bell that accommodates the animal’s only orifice as well – it is a double-purpose organ that serves as a mouth and as an anus as well.
Scientists have found that coloration is closely related to size. Larger individuals feature more vivid colors, crimson and deep purple being the two most common hues, while smaller animals are usually tan or orange.

Lion’s mane jelly fish are short-lived creatures, usually living only for one year, most of which they spend in the open seas, very rarely settling in bays. They prefer the company of other species such as shrimps and butterfish and they mingle with them for protection. They need all the protection they can get because they are the preferred treat of many other marine species such as leatherback turtles and birds. The lion’s mane itself feeds on small fish, other jelly fish such moon jellies, and plankton.

In terms of proliferation, these large creatures are very similar to other jelly fish species. They are able to reproduce sexually and asexually as well, the former being chosen when the animal is in the medusa stage, while the latter being the method chosen in the polyp stage. The fertilized eggs are carried by the female individual on her body, among her tentacles and are released only after they hatch into larvae. The mother then deposits the larvae on rocky surfaces where they become polyps. They start reproducing in this polyp stage, while still attached to the substrate and they also continue to grow there. They break free when they reach the following stage of development, the ephyra stage, after which they soon become fully developed hair jelly individuals.

Halitrephes Maasi Jellyfish

Halitrephes Maasi Jellyfish Bizarre Sea Creatures
Credit: E/V Nautilus

The spectacular Halitrephes Maasi jellyfish was discovered at a depth of around 1,200 meters near Baja California, in Mexico, but since its discovery, the critter has been found in both temperate and tropical waters, in the Atlantic, the Pacific, the Mediterranean, the Indo-Pacific and the Antarctic.

The creature’s recent discovery has given scientists little time to research it – that’s why very little is known about this special jelly’s life cycle, behavior and eating habits.

Normally, this deep-sea jelly floats in the obscure, deep water, making no show of it, but scientists discovered it due to its special ability to respond to light with colors. The deep waters where the animal lives are sampled and analyzed with the help of remotely operated vehicles that use strong headlights. The Halitrephes Maasi was discovered accidentally, when it was caught in the beams of an underwater vehicle and the creature reacted to the presence of strong light with a spectacular, multi-colored light show that looked like an underwater show of fireworks. It turned out that the radial canals in the transparent, gelatinous body of the animal form a starburst pattern that reflects the light, responding with spectacular colors, including pink, orange and purple.

The discovery of the Halitrephes Maasi jellyfish has given new impetus to deep-sea explorations – while the development of remotely operated exploration vehicles has already led to the discovery of many new species in recent years, the deeper these vehicles can penetrate the depths of the sea, the more new creatures they will reveal.

Hooded Nudibranch

Hooded Nudibranch Bizarre Sea Creatures
Credit: Joel Sartore

The hooded nudibranch, scientifically known as Melibe leonine, is a predatory nudibranch species that lives in the eastern Pacific Ocean, between Baja and Alaska. It prefers the shallow waters where there is plenty of kelp and seagrass, so the deepest layer that it has been found so far was 37 meters.

The hooded nudibranch grows to around 10 cm in length and reaches about 2.5 cm in width. The creature was named after a special body part, the expendable, sizeable oral hood that can reach the length of around 5 cm. Hooded nudibranchs are different from other nudibranch species not only because they have a hood, but also because they don’t have the chitinous plates in the stomach that the other species have.

While most nudibranch species feed on sessile creatures, such as sponges, the hooded nudibranch prefers planktonic invertebrates, such amphipods and copepods. This beautiful hunter is completely unable to chew, so it swallows its prey whole. While feeding, the individuals of this nudibranch species first attaches itself to the sea floor, then they pull back their hood, they thrust the hood forward to trap the prey. When the hood catches a victim and is closed, several rows of interlocking, small cirri are released to hold the prey in place. The hood then compresses even more and pushes out excess water while also pressing the captured prey downwards, to the mouth. The hooded nudibranch is quite fast, too – the entire process takes only about 4 seconds.


Isopods Bizarre Sea Creatures
Credit: British Antarctic Survey

Isopods are crustaceans belonging to the order Isopoda. With over 10,000 described species, they occupy the marine environment as much as fresh water and terrestrial habitats. Most of these animals are small in size, with segmented exoskeletons and jointed limbs. The fact that the legs are of the same type brought them the name isopoda, which from Greek translates into “same foot”.

Isopods are part of the larger group Peracarida, with the shared characteristic of having a special brood pouch which plays an important role in brooding eggs. There have been described about 10,215 Isopoda species, and these are classified into 11 suborders. Out of these, around 4,500 species occupy the marine environments, living mostly on the sea floor, with the rest being disproportionally scattered – 500 in fresh water and 5,000 species on land. At lower sea levels, species from the suborder Asellota are predominant, having adapted to the conditions of that environment.

Most isopods are scavengers and have an omnivore diet. Land species are mostly herbivore, while marine species feed on algae, bacteria, detritus, with some species feeding on small animals on the bottom of the sea floor. Some species have adapted to living a parasitic lifestyle. All species from the suborder Cymothoida live as parasites, while in the case of the suborder Flabellifera, only a part of the species are parasitic.

Parasitic species are mostly external, and they fix themselves unto fish, feeding on blood. Some have specialized piercing and sucking mouthparts, and some have clawed limbs that help them attach unto the host. An interesting case is that of Cymothoa exigua parasites the spotted rose snapper fish. It destroys the tongue of the fish and then it replaces it, without causing any further damage to the fish. This is the only known case of a parasite that functionally replaces an organ of the host.

While most terrestrial Isopoda species are pelagic, in the case of marine freshwater species, they are exclusively benthic. Their primary mechanism of locomotion is crawling, with some species using appendages to bore holes into the sea bed. There are some species that have limited swimming capabilities, using their modified first three pairs of pleopods. The slow locomotion explains why they rarely disperse over new regions, and it also explains the vast amount of isopods that are endemic to restricted areas.


Krill Bizarre Sea Creatures
Credit: Wikimedia Commons

The krill are tiny crustaceans living in the ocean, found everywhere around the world. The name of the species is derived from the identically sounding Norwegian word, meaning „young fry of fish”, fry being the stage of life when the animal already looks like a mature fish and is able to feed on its own, but it still has no fins and scales.

Krill vary in terms of sizing: most of them are small, about 1-2 cms long at mature age, but there are a few species that grow to about 6-15 cms. They all have an exoskeleton that consists of three distinct parts: the head, the thorax and the abdomen. Most species feature compound eyes that adapt quickly and easily to the changing light conditions of the waters. As an appendage to the head, most animals also have antennae.
Different species have different numbers of legs. All species have five pairs of legs used for swimming and other leg pairs attached to the thoracic part of the animal’s body.

These tiny animals are filter feeders. Their mouth-like organs at the front of their heads form a very dense comb used for filtering nutrients out of the water. The food they are looking for include mainly phytoplanktons. Most of these creatures are omnivorous, meaning that they feed on zooplanktons as well as very small fish.

After these creatures emerge from the eggs, they go through several stages of development as larvae. They also go through several sessions of moulting, that is, shedding their exoskeletons when they become too tight – smaller species shed more often than larger ones and the frequency of moulting decreases as the animal advances in age. The length of inter-moult periods depends on the climate, on the species and on the availability of food as well, some species being able to moult even when food is scarce and their body size shrinks, making their exoskeleton too large.

Male krill deposit their sperm in the female’s body through an orifice called thelycum. The female then carries the sperm sack in her ovaries until the eggs are ready to be delivered. The number of eggs carried can reach several thousand, with the sack growing until it reaches about one third of the animal’s body.
These tiny, frail-looking animals are in fact very resilient and relatively long-lived. Some species live for as long as 6 years, while the majority of krill species live for about two years.

Mariana Snailfish

Mariana Snailfish Bizarre Sea Creatures
Credit: Adam Summers

The Mariana snailfish (Pseudoliparis swirei) is a creature living in the deepest spot on Earth, the hadal zone of the Mariana Trench in the Pacific Ocean (the term hadal comes from Hades, the underworld in Greek mythology). The animal’s known depth range is between 6,198 m and almost 8,100 meters, being the deepest-living fish on our planet.

The body of the Mariana snailfish is shaped and constructed to meet the special challenges bought by the extreme environment that it thrives in. The body is shaped like a tadpole and it is of a pale pink color. The standard length of observed individuals is around 29 cm, with a weight of up to 160 g. Their body is scaleless, with a single dorsal fin. This special, very hardy snailfish is one of the top predators of the area, its diet consists mainly of tiny crustaceans.

The critter was first seen in 2014, by a research vessel that went deep down into the trench, sampling the water and recording related data. After the first individual was captured, another 35 of them were caught over the next 10 days, then the species was lost site of for a couple years, to reappear on another underwater vehicle’s screen in 2017.

The animal was named this way as a tribute Herbert Swire, who circumnavigated the globe between 1872-1876 and who participated in the expedition that discovered the spot in the Trench where the Mariana snailfish lives, a depression called the Challenger Deep.

Mexican Walking Fish

Mexican Walking Fish Bizarre Sea Creatures
Credit: Wikimedia Commons

The Mexican walking fish, also known as Ambystoma mexicanum or axolotl in popular culture, is actually no fish at all – it is a tiny amphibian native in Lake Xochimilko, in Mexico. It used to have one more habitat, Lake Chalco in Mexico, but it was drained and its present habitat is also shrinking, what used to be a lake now consisting mainly of canals.

The Mexican walking fish is a cute animal. Mature specimens are 15-45 cm long, they have a flat head, lidless eyes and a face that appears to be smiling all the time. The sides of the head are ornated with external gill stalks that have filaments. Their mouth is lined with vestigial teeth

The Mexican walking fish was driven to near extinction by the end of the previous century. There were several surveys conducted in the natural habitat of the species to identify living specimen, but the expeditions that took place in 1998, 2003 and 2006 found no living axolotl. Another expedition was launched in the area in 2010 and it found two living specimen. The expedition’s findings lead to the creation of axolotl shelters intended to conserve the natural habitat of the species and to facilitate the proliferation of the species. Breeding in captivity has been successful so far.

This special ability – regrowing lost limbs – gives the animal special importance for scientific research and it has also given it special status in popular culture, being generally considered a mysterious creature of magical powers.

Munnopsid Isopod

Munnopsid Isopod Bizarre Sea Creatures
Credit: Monterey Bay Aquarium Research Institute

The Munnopsid Isopod (from the order Isopoda) has been spotted a couple of times, but not much is known about its life. The small crustacean is an inhabitant of the deep waters of the Southern Ocean and it looks like a breed mixed from alien critters and viruses, an appearance compared to no other being ever discovered on Earth. Though rarely seen and little researched yet, the Munnopsid isopod is believed to come from a 300 million years old line of ancestry. Fossil records of isopods date back to the Paleozoic and they are believed to have been very widespread on Earth back then, inhabiting freshwater and saltwater habitats as well.

After its discovery, the species has been classified as an isopod, a member of an order of small crustaceans that have a hard exoskeleton, several antennae, limbs attached to the thorax and other appendages on the belly that are used for breathing. The body is flattened to bear the extreme pressure of deep-water habitats. They are known to be benthic animals, living on the seabed, in the depth and this feature determines their diet as well: having reduced abilities to move, they are probably scavengers, feeding on the detritus and other deposits they find on the sea floor.

Under the tiny thorax, the Munnopsid isopod has an even tinier chamber in which it keeps the eggs during the brooding period. They might release several hundred young ones after hatching.


Ostracods Bizarre Sea Creatures
Credit: Wikimedia Commons

Ostracods belong to the class of Crustaceans, a large group of anthropods including such widely-known species like krills, lobsters or crabs. Their habitats include fresh waters and oceans alike, ostracod species being among the most varied and most wide-spread forms of Crustacean existence – they can be found in any wet place, including small ponds, even the tiny pools of water that form inside flowers.

Ostracods are fairly small, their size ranging between 0.1-32 mm. The body of an ostracod consists mainly of a large head; a thorax, the part between the head and the abdomen; a small, often inexistent abdomen and the limbs. Almost all appendages are attached to the large head: the antennae used for swimming, the mandibles, the lower, jaw-like mouthparts used for eating and cutting and the maxillae or upper mouthparts.

What distinguishes Crustaceans – and with them, Ostracods – is the two-parted limbs, that is, limbs made up of several segments and branched into two.

Ostracod species take in oxygen through the branchial plates on the surface of their body. The majority of ostracod species have no circulatory system or heart, their vital fluids circulating among shell valves. They excrete waste through glands on their maxillae or through their antennae.

Ostracod species have a very sensitive sense of touch. Their bodies and limbs are covered in sensitive hairs with the help of which they feel their way forward. Though not very well-developed, some species have a single eye or compound eyes, too.

During reproduction, the two penises of the male ostracod unite with the two orifices of the female specimen. However, numerous ostracod species reproduce in a parthenogenetic, that is, asexual way, practically cloning themselves. The eggs produced by the female are released directly into the water or laid on the surface of plants. When the eggs hatch, the larvae already have a hard shell to protect them.

1. Some Ostracod species possess a special organ that produces a bluish light as defense against predators or as a way to attract specimen of the other sex for purposes of mating.
2. Fossils have been around for more than 500 million years.
3. Ostracod eggs are incredibly resistant, being able to survive drying and remaining viable for long periods of time, even years.

Finally, what’s most interesting is that ostracods can even resist being eaten by other animals like fish or birds – when they get eaten, they close their shells so tightly that in almost 30% of the cases they are able to get out on the other end of their predator, completely unharmed.

Pacific Hagfish

Pacific Hagfish Bizarre Sea Creatures
Credit: Mark Conlin

The Pacific hagfish (scientific name: Eptatretus stoutii) is a member of a family of fish that look like eels, but are not even remotely related to eels. One of its most typical feature is that it produces a slimy substance on their skin that emanates an odor perceived as foul by other inhabitants of the water and drives away all predators (when the animal senses danger, it can produce a huge quantity of the slime within seconds).

It is a species that has a wide distribution, being commonly found in the Eastern North Pacific, mainly between Mexico and Canada, its preferred depth being quite wide, between 16 and almost 1,000 meters.

The Pacific hagfish is no small creature – it can reach the length of over 60 cm (though most individuals grow to only around 40 cm). The body is quite colorful, too – the dark brown base color is spotted with blue and purple.

The Pacific hagfish, like all the other members of its family, does have some bones that can be considered rudimentary vertebrae, but they do not form a contiguous column (which accounts for the animal’s unique ability to tie nots from its own body. The animal is also jawless, and because of this it swims with an open mouth all the time. These special features and extensive research have led scientists to the conclusion that hagfish are creatures that have been around for around 300 million years and they have not changed much ever since they first appeared.

Pink See-Through Fantasia

Pink See-Through Fantasia Bizarre Sea Creatures
Credit: Larry Madin

The name of this beautiful creature of the seas, Pink See-Through Fantasia, suggests a magical appearance – and, indeed, this sea-cucumber species is all that. The creature has a translucent body of powder-pink color, with the internal organs, including the mouth, the anus and the intestines being completely visible, allowing the observer to follow the complete digestion process. The animal is not very big, the body size of the individuals usually stays in the 11-25 cm range.

The Pink See-Through Fantasia (scientifically known as Enypniastes eximia) was discovered in 2007 in the Celebes Sea of the Pacific Ocean, at the staggering depth of 2,500 meters. The animal is quite mobile – it propels itself with the help of its web-like swimming structures and it is able rise to the surface and to dive back down into the dark waters.

There is currently very little knowledge of the behavior and lifespan of the creature, all we have right now is general information about the Enypniastes genus, the family of species that the critter belongs to.

This little critter is beautiful when it is resting, but it is even more beautiful when it becomes agitated and starts glowing. The bioluminescence is used for scaring away predators – the process illuminates the area around the predator, making it visible for its own predators and convincing it quickly to stay away from the Pink See-Through Fantasia. The animal probably uses bioluminescence for other purposes as well, such as seeing in the dark.

Red Handfish

Red Handfish Bizarre Sea Creatures
Credit: Rick Stuart-Smith

The red handfish (Thymichthys politus) is a small, strange, angry-looking benthic creature that lives in the waters that surround Australia, more exactly Tasmania. Their preferred places are rocky areas, where they can spend time on top of the rocks as well as between the rocks and in the sandy areas at the edge of the reefs.

The name is a revealing one: the animal’s body is either embellished with bright red lines or is completely red and it often uses its hand-like appendages to move around on the sea floor, producing motion that is very similar to walking. It is a small creature, growing to only about 13 cm in length.

The red handfish proliferates through spawning, but it has a very low success rate and even that low rate depends on the availability of green algae that seems to be indispensable for the spawning process to take place at all. Scientists believe that the animal feeds on very little, almost invisible worms and tiny crustaceans.

The species had been discovered in the 19th century, near Port Arthur, but no individuals were encountered for a long time, until the 1980s, when a small population was discovered. In the 1990s, another group of ten specimens was encountered around the reefs off Primrose Sands, but the scientists who returned to the area in 2005 found no red handfish there. According to the estimations, however, there might still be around 1,000 individuals out there, walking the seabed.

Red-Lipped Batfish

Red-Lipped Batfish Bizarre Sea Creatures
Credit: Vlad Karpinsky

The red-lipped batfish looks exactly as the name suggests: like a bat with red lipstick on. Also known as the Galapagos batfish, this unusually shaped fish lives in the waters of Peru and around the Galapagos, in the shallow waters that, in most, cases don’t exceed the depth of 76 meters, though there have been a few sightings recorded at around the depth of 120 meters as well.

These strange creatures are small, the largest specimens being around 20 cm long. Their body, as the name suggests, is bat-like. They have a compressed body, a spine that consists of 20 vertebrae and very reduced and modified fins. Their head is relatively large, with a sharp nose that has hairs around it.

They are fish, but they are almost completely unable to swim – they just walk around on the sea bed, looking for food, even though they lack proper legs as well, their walking instruments being modified fins. As a matter of fact, all the fins of this batfish species are modified, some for making movement easier, others for making resting on the sea floor possible. Their bodies are usually of a grayish light-brown color, with a white belly. Adult individuals have a special protrusion on their head called illicium that emits light to attract prey.

The bright-colored lip is the most conspicuous feature of the animal and it is also the most studied characteristic. The reason why the bright color is needed has not been completely elucidated yet, but some marine biologists think that it serves the purpose of distinguishing the animal during the mating season.

They reproduce sexually, by spawning, releasing eggs that turn into pelagic larvae. They are extremely long-lived creatures – scientists think that they can live up to 200 years if they manage to find a spot where food is plentiful and water temperature, sea floor composition and depth are also suitable. They are hardy little creatures and they don’t have many predators, so they will probably be around in hundreds of years from now as well.

These batfish are carnivores and they have a huge appetite. They would feed on mollusks, shrimps, crabs and tiny fish – they would practically eat anything that is meaty and comes their way on the sea floor. They use their illicium to attract the prey – the organ emits a chemical that fluoresces in the water, luring tiny crustaceans to the batfish. This awkward predator has nothing else to do than snatch the prey and swallow it. Occasionally, batfish even mimic swimming, by drawing up their “legs” to go after their chosen prey, but they are not very good at it.

Scotoplanes Sea Pig

Scotoplanes Sea Pig Bizarre Sea Creatures
Credit: Monterey Bay Aquarium Research Institute

The Scotoplanes, commonly known as the sea pig or the Scotoplanes sea pig is a sea cucumber genus that lives in the depth of the abyssal plains of the Atlantic, Pacific and Indian Oceans, in habitats the depth of which ranges between 1,200 and 5,000 meters, but they have been found in other seas around the world as well. In some areas, they are so widespread and numerous that they make up around 95% of the total weight of benthic critters. The genus comprises three species, the Scotoplanes angelicus, the Sc. Globose and the Sc. Mutabilis.

The Scotoplanes is called “sea pig” for a reason – the creature looks like a tiny pig walking the seabed, indeed, with its plump little body moving around on plump little legs. The small creature is also pink, like a true piggy, the only feature that does not fit piggies being its size – Scotoplanes are about 4-6 inches long, small enough to fit into the palm of a human hand.
The diet of the Scotoplanes sea pig consists of waste, just like the diet of real land pigs. They walk around on the seabed, scouring through the mud to find tiny scraps of food. When they come across some delicious treats, they deploy their feeding tentacles that are used for sifting through the mud. One of their favorite treat is corpses that have fallen recently from the surface, such as the dead bodies of whales.

The sea pig’s body carries around numerous parasites, such as crustaceans and snails that bore holes in the skin of the pig and feed on the host’s body from the inside.

Sea Angel

Sea Angel Bizarre Sea Creatures
Credit: Alexander Semenov

The sea angel (scientific name of the genus in Latin is Glymnosomata, while the name of the species is Clione limacina) is a species of sea slugs that looks angelic, indeed, with a tiny, transparent body, a head that has tiny projections that serve as sensory organs and parapodia, that is, little appendages that look like wings that are flapped to enable movement. This angel of the waters is so small that it is almost unnoticeable – the largest specimen are only about 5 cm long.

The sea angel’s habitat is widespread, they are found in almost every sea and ocean of the world, from the Equator to the Poles. In some areas, they might be found alone, but sometimes they congregate to form large groups of several hundred individuals.

The serene appearance hides an ambush predator. Being slow-moving creatures that are capable of high-speed movement only on very short distance (they have special muscles for performing swift movements, but those muscles cannot work for too long), hiding and ambushing their prey is the only way they can avail themselves to food. While some types of sea angels feed on many different types of small prey, others feed exclusively on their own distant relatives, the sea butterflies. After capturing the butterfly, the sea angel deploys another one of its special organs, the tentacles that grasp the prey, then the little predator simply scoops out the precious parts or devours the victim whole.

Sea Fleas

Sea fleas Bizarre Sea Creatures
Credit: Hans Hillewaert

Sea fleas (Lat: Podonidae) belong to an order of small-bodied crustaceans also known as Cladocera in Latin. While the majority of water flea species live in fresh water, there are about eight species that live in oceans, especially in coastal areas or in seas that are relatively closed, with an abundant supply of sweet water. These small creatures are very exciting, especially as they are able to survive even the harshest of climatic or weather conditions.

Sea fleas are small, their size ranging between 0.2-6 mm. The characteristic shape features a small, downward-angled head and a body that seems unsegmented as it is covered integrally by the carapace. Under the shell, the body is segmented, with a visible division line between the abdomen and the thorax. Most species have one compound eye and one ocellus, that is, a simple eye as well. The head also has a pair of unsegmented, smaller antennae and another pair that is longer, segmented, with powerful muscles used for swimming.

The mouth of sea fleas is also small, even compared to their body size, but very complex, consisting of mandibles, maxillae, labium and labrum. The thorax of the sea flea is also compound, being divided into 5-6 haired appendages.

The majority of sea flea species reproduce in both sexual and asexual ways. The choice of the reproduction method depends on the quality of living conditions – among favorable conditions, the preferred mode of reproduction is parthenogenesis, that is, asexual reproduction, with exclusively female off springs. Males appear only when living conditions become unfavorable. In these periods, the pairs of fleas start producing eggs that can lay dormant for years that are carried by the wind and start developing and hatching only when they reach a territory with more favorable living conditions.

Water fleas, including the species that live on or around the sea, are filter feeders, striving on algae and detritus of various types. Podonidae feed by making water currents with their legs, currents which bring nutrients to the animal’s digestive tract.
Even though the water fleas striving around salt water are among the smallest living beings on earth, they are also among the most populous and oldest species. There are numerous flea species that have already been catalogued, but scientists still have a long way to go until they can say the incredible world of sea fleas has been properly mapped.

Sea Pens

Sea Pens Bizarre Sea Creatures
Credit: Richard Ling

Sea pens are a large and varied group of bottom-dwelling marine animals. There are more than 300 different species belonging to the group, with only some of them resembling the ancient quills they were named after, the others lacking the feather-like protrusion, looking more like clubs sticking out from the sea floor.

Sea pen species are actually octocorals, that is, soft corals that have a polyp and eight tentacles. However, the polyps of the sea pen behave in a way completely different from other corals. As the sea pen develops, one of the polyps transforms into an erect and rigid stalk and it eventually loses the tentacles, too, becoming the pen’s root, while the other polyps start growing out of this root. The lower part of the stalk anchors the pen to the substrate, while the others keep growing and forming complex branches. The exposed, visible part of the sea pen can grow very tall, some colonies rising taller than 2 meters. In terms of coloring, they are really varied, with yellow, orange and white being the most common hues.

Unlike most corals, sea pen species live in warm, but relatively deep waters, rarely settling in areas where the water is less than 10 meters deep, with some of the species being found very deep in the water, sometimes as deep as 2,000 meters. Their habitat ranges from southern California to the Gulf of Mexico, but they have been found in polar waters and in most habitats occupied by soft corals, too.

Sea pen species feed mostly on planktons, filtering them from the water with the help of their polyps and they are also known to capture small particles of food with the help of their tentacles. They reproduce by means of synchronized spawning, releasing eggs and sperm into the water. Fertilized eggs become free-floating larvae that spend about a week drifting in the water before they find a patch of substrate suitable for settling. Some sea pen species reproduce seasonally, while others proliferate the year round if the conditions are right. If scientists are right and rings on the pens develop at a one-a-year speed, some of the larger pens can be 100 years old or even more.

Being very sensitive creatures, these octocorals have developed a number of defense mechanisms to protect themselves. Most pens are able to engage in bioluminescence, the release of greenish light when they are touched or otherwise stressed in order to drive away the stressor. As another interesting feature, these pen-like animals are able to move to a certain extent. They are fastened to the sea floor with their stalk, but they are able to reach upward to catch food and they are also able to withdraw into their stalk if they sense any danger. If they are un-rooted and removed from their spot of substrate by stronger currents, sea pens are also able to re-anchor themselves.

Spook Fish

Spookfish Bizarre Sea Creatures
Credit: Monterey Bay Aquarium Research Institute

Barreleye fish, or “spook” fish are a curious and uncommon species of deep ocean fish that basically move around like “ghosts of the sea”, lingering at the edge between surface waters lit by sunlight and the darker depths of the deep ocean. These fish are cunning predators that are able to easily avoid being caught, while feeding on zooplankton and small fish. Some members of their species also have distinctive features that are extremely unique, as well as quite shocking for anyone not accustomed to the seeming strangeness of deep sea creatures.

Barreleye fish are a curious type of deep ocean fish found primarily in areas of the Pacific, Indian and Atlantic oceans. They mostly prefer temperate waters, and their distinctive, barrel-shaped eyes are their most interesting feature, as well as one of their most potent tools for finding prey. Barreleyes can either be very slender, featuring elongated, “aerodynamic” shapes for slicing through the water more easily, or stout and somewhat larger. The large, curiously shaped telescopic eyes that constantly gaze upwards, as well as their sizable dome-shaped heads and toothless mouths are among their most distinctive features.

Barreleyes are able to detect their prey far more easily than most types of fish, due to their specific development and evolution. Unlike many types of deep water fish, barreleyes don’t go deeper than about 2,500 meters. In fact, they are more commonly found at a depth between 400 and 1,500 meters, and are known to inhabit places where the depth allows the light to just barely penetrate through the denseness of the water. This way, they can see their prey from below, while not being spotted as easily. The large number of rods in their eyes allow spook fish to spot even the slightest movements and the faintest light flickers coming from the above silhouettes of their prey. They can, therefore, accurately spot the location and predict the trajectory of even the smallest zooplankton and various pelagic crustaceans that they commonly feed on.

The curious evolution of spook fish have made them not only very efficient when stalking and detecting their prey, but also extremely well-versed in blending into the environment and avoiding predators. One of their main defensive strategies is based on counterillumination – the process of blending with the ambient light from above, so that any predator viewing them from below would find it difficult to detect them. This is precisely where the “ghost-like” qualities of these fish can truly be seen most clearly, as their reflective soles are able to complete the job of hiding them in the background quite well.

One distinctive barreleye species known as the Pacific Barreleye will really end up spooking you, due to a distinctive, ghostly feature that was enough to shock scientists when they first examined this weird fish: its head is completely transparent. The Pacific Barreleye can be found in North Pacific waters around depths of 400-600 meters, and its fluid-filled, transparent head mainly allows it to have a much wider angle of sight. A solitary fish, the Pacific Barreleye is also an opportunistic predator, managing to often steal small fish out of the tentacles of various siphonophores.


Squidworm Bizarre Sea Creatures
Credit: Larry Madin

The squidworm (Teuthidodrilus samae in Latin) is a detrivore living in the water layers close to the seabed in the Celebes Sea, around the Philippines and Indonesia, in the area known as the Coral Triangle. The tiny worm prefers the lowest sea beds and was found at depth of 2,800 meters. The species was discovered in 2007, during the Census of Marine Zooplankton, carried out with the help of remotely operated, unmanned marine vehicles.

The squidworms observed so far are 9-10 cm long and about 1 cm wide and they look exactly as one can expect based on the name: though the creature is a true worm, it looks as if it were half worm and half squid. The animal’s segmented body is light-brown and semi-transparent, with an outer sheath of gelatinous substance and it has 10 appendages, two of which are used by the animal to avail itself to food, while the other eight play other, sensory roles. The squidworm has four pairs of gills. The internal organs are clearly visible through the transparent body.

The squidworm does feed on marine detritus. However, being a slow mover and an even poorer swimmer, it is not able to do much to satisfy its appetite, so its preferred way of getting food is suspension eating – it floats around and eats whatever small debris it can find in the water (material known as marine snow and consisting of decayed particles of animals, plants and feces).

Stygiomedusa Gigantea

Stygiomedusa Gigantea Bizarre Sea Creatures
Credit: Monterey Bay Aquarium Research Institute

Stygiomedusa Gigantea is a huge jellyfish living in the deep areas of seas and oceans of the world, preferring the depth of 800-1,700 meters. The animal is considered by many to be a monster and indeed, its huge body and the even larger drapes that hang behind the bell that name.

The bell-shaped body of the Stygiomedusa Gigantea can reach the diameter of 1 meter, while the curtain is often over 10 meters long. The critter has no tentacles, the flaring, long oral arms being the only external organs attached to the body. When the animal moves, it is flaring its oral arms, but scientists are still not completely sure about the role of the curtains. Many experts and researchers believe that the role of the scary, black drapes is to transfer every food particle from the water in front of it into the creature’s mouth.

The creature was discovered over a century ago, but detailed scientific information about its life and habits is still scarce due to the difficulties posed by observation. Only 115 sightings of the animal have been recorded so far, but even so, scientists believe that it is a widespread species. Like it is the case of so many mysterious creatures of the dark and little-known deep seas – footage of such creatures was recorded with cameras mounted on remotely-operated, unmanned underwater vehicles.


Sunfish Bizarre Sea Creatures
Credit: John ‘K’

The sunfish, also called the ocean sunfish or Mola mola in Latin is the heaviest bony fish discovered by scientists so far, with fully-grown specimen usually weighing between 247 and 1,000 kg (the weight of an average passenger car). The native of the tropical and temperate water earned its Latin name based on its appearance – the term means millstone and it refers to the grey color of the animal’s body and to its round shape that confers it an appearance similar to a huge piece of stone. The sunfish prefers surface waters and it likes sunbathing a lot, but it is an able swimmer, often found diving to over 800 meter deep.

The creature was initially thought to be quite passive, feeding on slow-moving animals, such as jellyfish, but they turned out to be excellent predators that move miles and miles each day and are quite choosy when it comes to food. According to recent studies, the stone-like fish does not eat all the prey it captures, it picks the most energy-rich parts of the jellyfish and leaves behind the rest.

In the 17th and 18th centuries, the fish was considered to be so valuable in Japan that shoguns accepted it as a replacement for money. However, there are other cultures that believed killing it would bring bad luck – Polynesians thought that killing a specimen would stop their staple food, mackerels, from coming to them.

Tasselled Wobbegong

Tasselled Wobbegong Bizarre Sea Creatures
Credit: Elias Levy

The tasselled wobbegong (Eucrossorhinus dasypogon) is a carpet shark species and a dweller of the intertidal waters around Australia and New Guinea, usually living in depths around 50 meters.
The animal is quite large, most specimens reaching the length of 1.8 meter, but many growing to almost 4 m. The shark’s body is very wide and flat, the width of the head exceeding its length. Like so many others in the class, the creature is ornated and looks like a carpet embellished with small, regular patterns and its back features dermal lobes that create a fringe-like structure. The animal has a large mouth located above the eyes and lined with 23-26 rows teeth on the bottom and 19 rows of teeth on the upper jaw, out of which the ones in the middle are like fangs. The body has large, rounded fins on the pelvis and tall ones on the back.

The tasselled wobbegong is a predator that is more active during the night, feeding mainly on bony fish, cephalopods and crustaceans. It can swallow prey that is almost the size of its own body, there is a documented case when the creature swallowed another shark whole.

The wobbegong is a huge creature, but it can hide like no one else. It certainly needs a good way to hide because it is a poor swimmer that is not very active, capturing its prey by ambushing it from caves.

Terrible Claw Lobster

Terrible Claw Lobster Bizarre Sea Creatures
Credit: World Register of Marine Species

The terrible claw lobster (or Dinochelus ausubeli, which literally means “terrible claw”) lives up to its name – it looks terrifying, indeed. However, the sight is awful only from up close – this crustacean is just around 3 cm long when fully grown. The lobster’s tiny body is translucent in most parts, with some pink and red coloring o the tail fan and on the middle of the body and on its two claws of two different sizes, one of them terrible, the other one horrendous.

The creature was discovered not long ago, in 2007, during a Census of Marine Life and it was fist described three years later. The word “ausubeli” in the Latin name refers to the marine scientist who supported the efforts of the researchers carrying out the census, Jesse H. Ausubel. According to the research conducted to map its habitat, the animal lives in one area only, in the waters close to the coast of Luzon, in the Philippines, in the depth of around 250 meters. The terrible claw lobster is a strange species not only because it looks strange and inhabits a little area, but only because not many of these animals have been seen yet, that’s why they are so mysterious.

The creature cannot see at all, but that disability does not stop it from using its claws with great dexterity. The claw is not just a simple tool for grabbing food – it is serrated with lots of teeth to make it look even scarier.

The Vampire Squid

Vampire Squid Bizarre Sea Creatures
Credit: Steve Downer

The vampire squid is a curious creature that, at first, seems like it just crawled out of a genuine horror movie, while its name is equally intimidating. In spite of its scary appearance and name, however, this cephalopod dwelling in the deep ocean is known to be quite small – growing to be only about 6 inches in length, while its body resembles more that of a jellyfish, rather than a “genuine” squid. Its large eyes, unique light producing organs and somewhat strange and illusive behavior have turned this “vampire of the deep” a worthy topic of discussion in scientific circles.

Originally discovered in 1903 – and mistakenly described as an octopus – the vampire squid features a pair of large, intricately shaped fins on the top side of its body, resembling wings, while it has no less than eight arms that it can use similarly to a web when it’s attacked. Its gelatinous form makes the vampire squid look very much alike to a jellyfish, and its mode of propulsion through the water also reminds scientists of jellyfish that expel water for the purpose of moving through it more easily in almost the same manner. The squid’s eyes are quite large and can seemingly change color from red to blue – depending on the lighting. Also, a curious feature is represented by the squid’s powerful beak-like jaws that are strong enough to completely destroy the shells of crustaceans.

Commonly found at depths exceeding 600 meters, the vampire squid is an excellent example of a genuine, deep diving marine creature. This species is known to commonly thrive in an area called the oxygen minimum zone (OMZ) – a region of the ocean recognized by its low O2 saturation. To be capable of surviving in this unforgiving environment, the squid has adapted to develop the lowest mass-specific metabolism and most effective hemocyanin binds of all cephalopods. Their significantly larger gills help with this action, while the animal’s increased agility and balance allows for greater freedom and maneuverability obtained with less effort.

Not much is known, as of yet, about the natural behavior of the vampire squid, as observed in its normal habitat. The squid is believed to feed on prawns, cnidarians and various other smaller invertebrate species, while some larger deep diving species are known as its predators – including whales, seals and various types of fish. Unlike most of its cousins living in the more hospitable areas of the oceans, vampire squid have to deal with the low density of prey and harsh environment of the OMZ. As a result, they have also adapted a variety of unique deep-water predator skills and creative hunting techniques based on sudden, erratic movements and trajectories.

The vampire squid is still a very little understood deep water creature. While a few specimens were captured, it was difficult to study anything but their defensive behavior. Most have either been injured or died immediately after capture. Also, very little is known about the reproductive habits of the squid, as well as their development and transition to adulthood. Scientists did manage to at least identify the fact that there may be no actual breeding season in this case and the resizing and repositioning of the fins are a distinctive sign of the squid’s growth and development. However, many researchers admit there isn’t much data to work with, while continuing their attempts to research this unique and mysterious creature.

Triplewart Seadevil

Triplewart Seadevil Bizarre Sea Creatures
Credit: Danté Fenolio

The triplewart seadevil (Cryptopsaras couesii) is a devilish creature of the waters, very common in all oceans and seas. The range of depth that they inhabit is as wide as their geographic distribution – they have been found as low as 4,000 meters and as high as 75 meters, most of them preferring the range of 500-1250 meters. They are especially abundant in the South China Sea.

The triplewart seadevil is a member of the anglerfish family. It has a dark-colored longish body that looks oval when observed laterally. The head is large and has a mouth that is almost vertical when closed and lined with 2-3 lines of teeth. The body features lots of spines that are embedded deep into the skin, with only the tips protruding. As the name suggests, the animal’s body has three warts, three caruncles right in front of the dorsal fin, on the back. The eyes are very small.

These seadevils are capable of bioluminescence, a feature that they use for attracting prey.
The male individuals belonging to the species look entirely different from the females. While male specimens are only 1 cm long while living separately, females can grow to 20-30 cm. The tiny males become parasites that thrive on the female’s body, after which they almost double in body size. The females are oviparous – that is, they lay eggs, the young ones being born through hatching. The eggs are believed to be preserved in gelatinous rafts


Viperfish Bizarre Sea Creatures
Credit: JesseClaggett

Viperfish are fierce and they also look extremely mean. The maximum length of the animal’s thin body is 60 cm, but the face split by a large mouth lined with sharp and pointed teeth that are so long that they prevent the creature from closing its mouth can scare even the dwellers swimmers of the deep sea.

Viperfish are members of the Chauliodus genus and are called bathypelagic creatures, which means that they live in the depths of the ocean, mainly in the Atlantic and the Pacific, in layers that humans cannot access, where the pressure is so strong that the human body would simply crash. The special conditions account for the animal’s special body shape, that is why it is so long and thin.

In terms of its diet, the viperfish does not seem to be choosy at all: it would eat anything it finds, including small crustaceans, other fish and bristlemouths. The viper captures its prey with its long teeth, piercing it, then the victim is passed into the mouth. The fish also has photophores along its belly, organs that emit light to attract the prey.

The creature is quite long-lived – scientists believe that they can live for 30 or even 40 years.
The animal never stops looking for food, it migrates constantly within its habitat range, from the bottom of the range at 1,500 meters to the top of the range, to the depth of about 600 meters. They cannot survive anywhere higher than that level – if they are captured in nets that drag them higher up, they die very soon.

Whitemargin Stargazer

Whitemargin Stargazer Bizarre Sea Creatures
Credit: Rickard Zerpe

The whitemargin stargazer, also known as pop-eyed fish or tube-nosed stargazer, is one of the strangest creatures of the Indo-Pacific region, especially around Fiji, Tonga and Samoa. The feature that gave them their names is that their eyes are located on the top of their heads, so they are not looking ahead or around them, but towards the sky.

Stargazers prefer warm and shallow waters where the sea floor is covered in sand or mud and is suitable for hiding. They live in waters 5 to 350 meters deep. There is a very good reason why these strange creatures wear their eyes, their mouth and their nostrils on the top of their heads: they spend most of their time buried in the sand of the substrate and they feed on prey that swims above them, so their senses have adapted to their peculiar lifestyle.

It is not only their eyes that allow stargazers to live in hiding. Their relatively large bodies (individuals vary in size, but they stay in the 20-80 cm range) are colored in hues similar to the color of the sand they live in, providing with camouflage so efficient that they are hardly noticeable, even when they are not buried.

Stargazers have several other very special features that further increase their success as predators. They have a special organ behind their eyes, actually a kind of modified optic nerve that charges electrically, sometimes up to 50 volts, and is used by the fish to electrocute their victim before snatching it and they also have a lure similar to sticky tongue for capturing prey more easily. The lure does not look like a lure at all, it sticks out from the mouth of the fish in hiding looking more like a worm and attracts the prey right above the stargazer, allowing this camouflaged predator to snatch its prey and devour it. They also have venomous spine that release a powerful toxin to protect the stargazer against predators.

Stargazers have another special organ on their head called cirrus, an appendage located on the edge of their mouth – it fulfills the role of preventing the animal from swallowing sand or mud while waiting around buried in the substrate. They feed on any prey they can catch, including octopuses, squids and fish. They use their sticky tongue to catch the prey and their numerous teeth to tear it apart.

Very little is known about the reproductive techniques employed by these strange fish. What is known, though, is that male and female individuals look different and they reproduce sexually. They mate seasonally, reproducing mostly during spring and summer. They live in shallow waters, but, when the time comes for the female whitemargin stargazer to lay her eggs, she looks for an area that is shallower than the usual habitat and she lays her eggs there.


Wolffish Bizarre Sea Creatures
Credit: Amanda Graham

The name wolffish can refer to any of the five species that belong to the family of Anarhichadidae, one of the largest fish families, with the highest number of species belonging to it. They are all perciform fish, that is, they are ray-finned fish characterized by separated dorsal and anal fins, a spined pelvic fin and five soft rays. The dorsal fins are long and comprised of over 50 spines. They all have strong molar and canine teeth that they use to crush their prey consisting of crustaceans, crams and echinoderms that they capture on the sea bottom.

The body of wolffish species is flat and elongated, covered in small scales that are not overlapping. The largest individuals in the family can grow quite long, reaching the length of almost 2.5 meters. The strong teeth of the creature are dangerous not only for the prey that it feeds on. The fish is known to bite when startled and to inflict very serious pain, even if the bite does not serve the purpose of feeding.
Wolffish species have a wide distribution, being quite common in the North Atlantic Ocean as well as in the North Pacific. They prefer habitats located on the continental shelf and waters that are around 600 meters deep.

The Atlantic wolffish lives in very cold environments and to be able to withstand the freezing water, it developed the ability to produce a natural antifreeze substance in its body.

Yeti Crab

Yeti Crab Bizarre Sea Creatures
Credit: David Shale

The official name of the yeti crab is Kiwa hirsute, a name that also makes reference to being hirsute, that is, hairy. The decapod crustacean was discovered not so long ago, in 2005 in the South Pacific Ocean by an expedition organized by the Monterey Bay Aquarium Research Institute in the area of the Pacific-Antarctic Ridge.

The creature is as strange-looking as the snow monster it is named after. It has reduced eyes that have no pigment, just like the rest of the body that is white, too. The lack of pigments in the eyes has led scientists to think that the animal is blind. It has pincers with long hair on them and are inhabited by bacteria that help the host with the detoxification process (the crab prefers habitats in the proximity of hydrothermal vents where the water is loaded with minerals). The animal can grow to the size of around 15 cm and it is known to be long-lived, too, its lifespan reaching 20 years.

The diet of the yeti crab is not fully known, but some strange features have been confirmed. It is supposed to be carnivorous, but it is also known to feed on bacteria. The hairy legs of the creature serve as breeding ground for lots of bacteria, what’s more, the crab even tries to encourage the proliferation of these bacteria by waving its limbs around the hydrothermal vents. The crab does not do this unselfishly – the bacteria growing on its own body is among the host animal’s favorite dishes.

Whale in Ocean