Credit: Blane Perun


Zoanthids are marine organisms in course Anthozoa of phylum Cnidaria usually residing in compact colonies of numerous “polyps.” The group consists of the essential reef builders that inhabit tropical oceans, which secrete calcium carbonate to type a tough skeleton. A zoanthids “head,” which seems to become just one organism, is really a colony of myriad genetically identical polyps. Every polyp is usually just a few millimeters in diameter. More than numerous generations the colony secretes a skeleton that’s attributing with the species. Person heads develop by asexual reproduction of person polyps. Zoanthids also breed sexually by spawning. Polyps with the exact same species release gametes concurrently more than a time period of 1 to a number of nights about a complete moon.

Zoanthids divide into two subclasses, based on the amount of tentacles or lines of symmetry, along with a sequence of orders corresponding to their exoskeleton, nematocyst kind and mitochondrial genetic evaluation. These with 8 tentacles are known as octozoanthidslia or Alcyonaria and comprise soft zoanthids, sea followers and sea pens. These with greater than 8 inside several of 6 are known as hexazoanthidslia or Zoantharia. This group consists of reef-building zoanthids (Scleractinians), sea anemones and zoanthids.

At first thought to become a grow, William Herschel utilized a microscope to set up within the 18th Century that Zoanthids had the attribute thin cell membranes of an animal. Whilst a zoanthids head seems to become just one organism, it’s really several numerous person, but genetically identical, polyps. The polyps are multicellular organisms. Polyps are often a couple of millimeters across, and therefore are formed by a layer of outer epithelium and internal jellylike tissue recognized because the mesoglea. They’re radically symmetrical with tentacles surrounding a central mouth, the one opening towards the abdomen or coelenteron, via which meals is ingested and waste expelled.

The abdomen closes in the base with the polyp, exactly where the epithelium creates an exoskeleton known as the basal plate or calicle .The calicle is created by a thickened calcareous ring (annular thickening) with six supporting radial ridges .These structures develop vertically and undertaking in to the base with the polyp. Whenever a polyp is actually stressed, its tentacles agreement in to the calyx to ensure that practically no component is uncovered over the skeletal system. This safeguards the organism from predators and also the components. The polyp grows by expansion of vertical calices which sometimes septate to type a brand new, greater, basal plate. More than numerous generations this extension types the big calcareous structures of zoanthids and eventually zoanthids reefs.

Polyps feed on the number of little organisms, from microscopic plankton to little fish. The polyp’s tentacles immobilize or destroy prey utilizing their nematocysts. As soon as digested, the abdomen reopens, permitting the removal of waste items and also the starting with the subsequent hunting cycle. These poisons are often also weak to hurt people. An exception is fire zoanthids. Zoanthids polyps are very small, soft-bodied organisms associated with sea anemones and jellyfish. At their base is really a tough, protective limestone skeleton known as a calicle, which types the framework of zoanthids reefs. Reefs start whenever a polyp attaches by itself to some rock around the sea floor, then divides, or buds, into 1000’s of clones. The polyp calicles connect with 1 an additional, making a colony that functions as being a single organism. As colonies develop more than hundreds and 1000’s of many years, they join along with other colonies and turn out to be reefs. A few of the zoanthids reefs around the planet these days started expanding more than fifty million many years back.


Zoanthid, Reef Corals
Credit: Blane Perun

After observing zoanthid polyps for years I have noticed that some grow very quickly while others will grow so slowly that if they grow a few button polyps each year then they are lucky. When they have comparable stock sand oral disc size you would assume that they would respond similarly in the same conditions. However, with zoanthids that is not always the case and you never know what you might get! Because of this you will want to pay attention to the zoanthids and document their growth over time to compare them.

Most of the color morphs great at completely different paces despite looking the same and being in the same conditions. Because of this it is challenging to believe that they are the same species that have the exact same needs. When two colonies are identical on the reef and each year one appears to be considerably bigger than the other it makes you wonder whether the difference is just color or if it is an entirely different species.

When this zoanthid color morph appeared in Julian Sprung’s Invertebrates Guide it garnered quite the attention. The specimen had been photographed by Julian before and it is my most recognized zoanthid besides “Perun’s Purple People Eater.”

Of all the specimens I have worked with, this is the fastest growing and most aggressive. I have watched it slowly kill the tissue of a blue Acropora abrolhensis after surrounding it and it began taking over its base. This truly is amazing and totally worth documenting through photos.

The “Actinic Yellow” is the next aggressive zoanthid I have. Notice how it is growing beside a piece of heliopora. This coral is quick growing and can quickly take over everything in the aquarium. The heliopora colony’s growth was kept in check by button polyps.

It was amazing to watch the zoanthid colony defend itself from the heliopora aggression and to begin covering the colony’s perimeter. Heliopora is one of nature’s fastest plating corals. Pay close attention to the zoanthid colony because it will truly surprise you and it is worth paying attention to. Remember, zoanthids may not react the same in the same conditions even if they appear to be the same size. Because of this you truly don’t ever know what you will be getting.

Zoanthid Coral

Zoanthid Coral, Reef Corals
Credit: Blane Perun

Zoanthid coral has many common names that refer to it including sea mat, polyp rock, colonial anemones, button polyps, polyp rock, false coral, and the like. All of the genus in this article refer to the family zoanthidae, subclass zoantharia, class anthozoa. Members of the genus include protopalythoa, zoathus, palythoa, and isauraus as well as others. If you are just starting out with the zoanthid coral it helps to know all of the common names so you will be in the “know” so to speak. You could easily have someone ask you about “false coral” or “button polyps” and have no idea they are talking about zoanthid coral. Doing a little research is certainly worthwhile and can help you along the way in your quest to grow zoanthid coral.

There were more than 300 individual species described by Wilkens (1990) however realistically the amount seems to be considerably less. There is an overhaul in classification taking place that will reclassify some species and even genus in some situations.

The habitat of origin may affect the physical characteristics of the coral to some degree. In fact, there is the possibility that two colonies that are identical could look different. In high current areas it is more likely to find shorter zoanthid coral with smaller mouths. Low current areas are more likely to have specimens with larger mouths, elongated bodies, and longer tentacles.

It may seem amazing, but zoanthid coral occurs in many situations and extremes. In fact, zoanthid colonies have been observed in tidal areas where they were exposed to the air for hours upon hours as well in reef crests receiving blows from the waves. This shows how durable the zoanthid coral is and why it is such a good option for aquariums. Zoanthid coral will do well in most all aquariums.

Buds are formed on the base of the mated tissue to reproduce. The polyps are smaller and sediment is not incorporated into its base.

The tentacles pack the center of the oral disk significantly. The palythoa does have polyps that are larger, but they are also embedded into common tissue. As a result, it can have a variety of color combinations. The base of the palythoa and protopalythoa incorporate sediment and sand right into the tissue. It is believed that this offers support and protection.

Zoanthid Care

Zoanthid Care, Reef Corals
Credit: Blane Perun

Zoanthids care is based on importing and fragmenting or else on propagation. I have never witnessed larvae from sexual reproduction from zoanthids and protopalythoa in my tank, although it has been found in plankton (Sprung 1997). Since I have never witnessed this I am not necessarily expecting to. When it comes to the zoanthids I propagate asexual reproduction takes place and is what is behind all of the growth of the zoanthid species. Knowing about zoanthid care is important.

Small buds at the base of the mature polyps will appear with protopalythoa and palythoa. However, don’t plan on a large reproduction. The asexual reproduction takes place usually when the small polyps grow and become more dense as compared to the fleshy coenhehcnyme tissue they start out as.

Generally, when the zoanthid has plenty of room to spread the maturation process will usually occur on the perimeter. In the aquarium you actually have the physical means to control the polyps’ expansion. When I mounted specific corals in certain areas for added color I was very careful how I placed them in the system.

It is recommended to keep the rock away from all other rocks in an effort to contain the polyp. I frequently would glue rocks using epoxy for underwater purposes and it would appear to actually touch the rock structure when in reality it was several inches away.

Space is the most important thing when it comes to natural reproduction on the reef. If you want to sell the zoanthids then you will need to have sufficient current, nutrients, and lighting.

As long as you have these zoanthid care tips in your mind you need to also think about the placement of your colony. This is incredibly important and will determine how the zoanthids spread. If you want a special and rare color morph to spread over some rocks then you need to have proper placement. You can easily fund your operation by selling offspring zoanthids of rare blue or pink morph.

The first thing you will want to do to propagate your first zoanthids colony is to spread several cuttings onto small plugs. If you place the starters in intense light and in high current it should take about a month to take off. The time will go quickly so be sure to pay attention!

Zoanthid Eating

Zoanthid Eating, Reef Corals
Credit: Blane Perun

Zoanthids are not immune to predators and disease, which is obvious from the occasional problem of zoanthid eating nudis that many aquarists deal with from time to time. Most likely, zoanthid eating nudis come from the Pacific Oceans, specifically around the Solomon Islands.

Although vicious predators, zoanthid eating nudis are also known as being particularly beautiful, and use the undigested nematocysts of the zoanthids as a defense mechanism against their own predators.

Zoanthid eating nudis are quite resistant to predators, most likely because of their quick abilities to adapt to their predators. There are however a large number of specific species of fish that can pose a threat to zoanthid eating nudis, specifically wrasses and butterfly fish, but unfortunately these fish are not suitable for most home aquariums due to their size, price, and other attributes.

There are a small number of zoanthids that actually do not appeal to zoanthid eating nudis, so certain zoanthid polyps will be at higher risk of attracting zoanthid eating nudis than others. Generally speaking, it is more common for zoanthid eating nudis to prey upon the Zoanthus genus versus the Proptopalythoa or Palythoa genus.

It is very difficult to rid a colony of zoanthid eating nudis once the manifestation has taken hold. One method to try and eradicate zoanthid eating nudis in a colony is fresh water dips of the entire colony. However, this needs to be done frequently (once or twice a week until the zoanthid eating nudis are gone), as it takes more than one fresh water dip to kill zoanthid eating nudis and their eggs. It is also recommended to diligently assess the zoanthid polyps for zoanthid eating nudis and to pick out the eggs sac and adults with tweezers or other fine combed method.

When purchasing zoanthids, avoid acquiring colonies whose polyps are not completely open, as zoanthid eating nudis could be a threat to that colony. If possible avoid purchasing long skirted zoanthids and instead concentrate on the short skirted specimens from Fiji, Tonga or Solomon Island. Some aquarists have suggested that zoanthid eating nudis prefer long skirted varieties because the overhang helps the zoanthid eating nudis to hide from possible predators. There is preventative action you can take to avoid predators like zoanthid eating nudis, among others, from infiltrating home aquariums. The answer is to quarantine every new coral specimen that is being added into the tank, just as is done for new fish.

Zoanthid Frags

Zoanthid Frags, Reef Corals
Credit: Blane Perun

Zoanthid frags are literally fragments of zoanthids that are farmed and sold for aquarists and marine enthusiasts for display in artificial environments. Zoantharia, the order of which zoanthid frags are a member, are found naturally as polyps and sea mats in coral reefs and oceans in the wild, usually in back reefs, over dead corals, or intertidal waters all over the world.

There are high populations of zoanthid in tropical and subtropical waters, and many zoanthid frags come from this area. Coloring and shape of zoanthid frags are extremely varied, and it is common to find sand or other pieces of sediment incorporated into the make and build of the zoanthid frag’s tissue.

Many aquarists desire study, hardy specimens and livestock for their home environments, and zoanthid frags are an ideal choice because of their tough resilience to environmental disturbances. Zoanthid frags are sold as “polyps” in a retail environment, which include a wide variety of species. There are some zoanthid frags available year round for purchase, including the “Zoanthus sociatus”, a bright green zoanthid frag from the Caribbean, “Zoanthus danae”, a species of zoanthid frag from the Pacific, “Parazoanthus gracilis”, an extremely popular zoanthid frag from Indonesia, and “Parazoanthus swiftii”, a zoanthid frag from the Atlantic

Because of their hardy nature, zoanthids sold as zoanthid frags are normally found in good shape, but there are a few things to keep in mind when choosing zoanthid frags for your home environment. Look for zoanthid frags whose entire polyps are open- the polyps do not all have to be open at the same time, but a health zoanthid frag will display open polyps.

If there are portions of the zoanthid frag that appear dead, or display white tissue or other material, do not purchase the zoanthid frag. Also, zoanthid frags need time to heal after they are cultivated from the original colony, so take care to only purchase zoanthid frags that have gone through the healing period.

The coloring of the zoanthid frag should always be deep and display the coloring all over the specimen- if the zoanthid frag has portions of dull or faded coloring, it is best to choose another zoanthid frag specimen for purchase. Although it is common for zoanthid frags to exist communally with other species (such as sponges and algae), do not purchase zoanthid frags that come attached with these specimens- they will quickly die when transitioned to an artificial environment.

Zoanthid Propagation

Zoanthid Propagation, Reef Corals
Credit: Blane Perun

Manual zoanthid propagation works well with the zoanthus due to its reproductive properties. The sea mat tissue will grow in one of two ways, either like spaghetti or else quite thick. Should it grow more like spaghetti it is possible to lift up a section towards the outskirts of the colony and then slowly and gently life the zoanthus from its rock.

There are a couple of options. You may want to cut some of the strips into sections and then mount them onto plugs using a plastic toothpick or else you may choose to use a zip tie to gently bound them. Using adhesive is helpful in many situations and I recommend it, however there are some polyps that do not react well.

An example of this is when I placed a bit of adhesive on a blue morph. Within a few days the tissue decayed and the entire colony disintegrated in time either as a direct result of the adhesive burn or because they decaying tissue created an environment for another infection. This might not be the rule, but it does happen so I use plastic toothpicks now to attach coral to a new substrate.

The next method used is by chiseling small pieces off the colony. This is done by chipping at the rock underneath the colony. If you split the rock then you can use a sharp blade to cut the tissue. When you can’t break the rock then use a Dremel tool or small screwdriver. This will result in flat rock pieces covered in polyps that can easily be glued to a reef plug. You must be very careful when it comes to glue and always pay close attention to what you are gluing.

Superglue gel was used to adhere the two month old propagation to a plug. In little time the plug was covered with the colony. This became the perfect piece to cut to sell or trade. Now, the plug may be cut down into more. This is a great tip for zoanthid propagation and something you will certainly want to keep in mind if you will be involved in lots of zoanthids propagation. If you are a good student and pay attention to the information outlined here then you should have no problems that can’t be overcome with experience when it comes to zoanthid propagation.

Zoanthid Toxin

Zoanthid Toxin, Reef Corals
Credit: Blane Perun

Evaluating the Physical Characteristics of Palytoxin: How Dangerous Is Zoanthid Toxin?
Zoanthid toxin, also known as palytoxin, is known by scientists to be the most powerful toxin known to exist in marine habitats. Present in the nematocysts and mucus of zoanthids, one of the most well-known types of corals, the toxin is capable of leading to death in humans without much deliberation. Fortunately, it’s not that easy to actually be affected by the toxin of zoanthids, so getting close to the coral isn’t necessarily a death sentence. In fact, most of those who have even handled zoanthids without gloves only experience mild pain and stinging as a result of nematocyst contact.

What Are Zoanthids?

Because of their striking appearance, zoanthids are among the most popular corals in the marine world. They are constantly observed and sought out by coral reef enthusiasts, and they are remarkably diverse when it comes to color differences. “Zoanthid” is a name given to all members of the order Zoantharia. A curious fact about zoanthids is their ability to incorporate sand and other small pieces of various materials into their tissues, in order to build their coral structures. While quite benign, these corals hide a terrifying secret: they house in their bodies one of the most potent toxin in the world, the zoanthid palytoxin.

The Most Potent Toxin in the Marine World

Palytoxin had a long history well before zoanthids were first discovered. Nicknamed “the deadly seaweed of Hana” by the indigenous people of the Hawaiian islands, zoanthids house a toxin that has been known to kill within minutes, when ingested in the right dosage. When entering the blood, the toxin can be fatal to humans, leading from hemorrhage, muscle weakness and ataxia to ischemia, pulmonary hypertension and death. Even cases of people inhaling small amounts of the toxin distributed by air through steam were known to develop severe health problems later on. Fortunately, the compound has a half-life of 55 to 85 minutes, and scientists have been able to determine that it does degrade under certain conditions.

Can You Die from the Toxin?

If the toxin actually enters your bloodstream, death is certain, since there is no antedote for palytoxin. However, it can be extremely difficult for that to happen under normal circumstances. The nematocysts can’t usually penetrate human skin, so unless they hit a cut or an open wound, you should be fine. Also, since much of the toxin is inside the mucus of the zoanthid, one would have to ingest the mucus itself in order for the effects to become deadly. So, as you can see, it’s virtually impossible to die as a result of being poisoned with zoanthid toxin, even though most experts be strongly against anyone taking any kinds of chances with these species of coral.

Feeding Zoanthids

Feeding Zoanthids, Reef Corals
Credit: Blane Perun

With many years of experience I have experimented with all kinds of food for feeding zoanthids. At times I would use turkey basters and pipettes to shout a small amount of food over the colonies. Sometimes it appeared that feeding zoanthids would react to the food and tentacles would appear and appear to take the food particles and take it to the mouth however it was never completely obvious whether this was a result to feeding or the reaction.

Feeding is much more obvious with the larger protopalythao and palythoa polyps. An example is when the soft shrimp pellets are taken quickly and the tentacles begin to take the food bits and take them to their mouth. If you see this occur then you will truly be amazed at the process.

When my dedicated system is completed I will begin to learn more about growth rates of palythoa and direct feeding zoanthids. I will compare the two identical colonies by feeding one directly and not the other one. By comparing other polyps I have only witnessed growth that is slow or moderate. With intervention the zoanthids will flourish quickly.

It is important to keep as many nutrients in the aquarium as possible because this will naturally expedite the reproduction of zoanthids. This makes sense because without nutrients feeding zoanthids would not be able to thrive.

My observations so far have led me to believe that by feeding fish heavily this produces a better environment than any direct feeding zoanthids does. It is not ideal to set high nutrients loads in reef aquariums and even if there were no other repercussions the zoanthids being live coral could over grow the tank.

If you are interested in zoanthids or palythoa then you should use your good judgment in how you aqua culture these. I suggest setting up a special system to do so, but that is just my opinion. It’s not necessary to have a complicated culturing vat but rather only the basics are necessary. Your tank will be strained less and your efforts will be rewarded by using a specialized system. Remember this before you get started because it truly is worth the extra work on the front end to have feeding zoanthids turn out like you had hoped.

Blue Zoanthids

Blue Zoanthids, Reef Corals
Credit: Blane Perun

Blue zoanthids are one of the most difficult to work with compared to other colors in nature. The pink zoas are similarly challenging like the blue and the information here is geared to working with both.

In general, blue zoas are found in the Pacific ocean. It is not uncommon for them to be imported from the Caribbean, too. Both of these blue zoanthids have needs that are very specific and different from one another. The blue from the Caribbean fare better during propagation than colonies from the Pacific.

Aggressive fragmentation affects a very large percentage of Pacific variation. The dying tissue from the cuts don’t get enough water circulation to heal. You will have a much higher success rate propagating small colonies starting with at 20 polyps. You can accomplish this by breaking the rock into smaller sections.

Another helpful tip is that blue zoanthids from the Caribbean handle high salinity better than Pacific blues, this was very apparent over a long period of time. I ended up separating the two variations and creating separate propagation systems for Caribbean blues and the Pacific blue zoanthids.

The last thing to keep in mind when it comes to zoanthids husbandry is aquarium lighting; this could not be more critical with blue color variation. I have kept these zoanthids in under various lighting hardware. Including VHO, HO, PC, MH, MH and PX, also testing every combination of these bulbs possible. After these experiences it was obvious that the Pacific blue zoanthids did not hold their color as intensely under bright lights. On the other hand the Caribbean blues tend to become more intense under bright light. Overall, it is much easier to keep the Caribbean blue zoanthids healthy and growing, but the most intense coloration comes from the Pacific colonies.

Green Zoanthid

Green Zoanthid, Reef Corals
Credit: Blane Perun

The zoanthid variety is quite amazing and I have never ceased to be amazed by it. Over the years that I have collected and propagated green zoanthid, and zoanthid in general, I have seen at least 100 variations in color if not more. The most abundant color is the green zoanthid. It is important to notice the colors of the green zoanthid and other zoanthids simply because there are so many variations. If you pay attention to begin with you will be amazed at the variations.

Two color polyps were the basis of my early stock. Since that time my brood stock includes at least four contrasting colors. There are exceptions of course and I always look out for the “solid color” zoanthid. Or, I look out for more than just the green zoanthid and focus on those that have striations or patterns on the oral disk. Also, I look out for rare colors that will contrast with the green zoanthid. Some of my favorites are discussed below.

There are many challenges to aquascaping a reef system for both novices and advanced aqua culturists. Some have a mechanical nature that can be solved by using zip ties and plenty of patience. Still others are much more challenging. Sometimes, the aesthetics seems impossible when you want to balance texture and color. I always try to keep a wide variety in my display system and even with collections that are very diverse they always seem to lean towards specific tones and shades.

The majority of my systems are made up of SPS , exotic leathers, and a variety of LPS. Stony corals were mostly green, blue, pink, purple or yellow. The most abundant seemed to be green and blue while sarcophyton and porities were yellow.

I had a bit of difficulty pulling the eye away from such a dominant focal point, partly because the yellow color was scarce, and secondly the porities were large colonies compared to the other SPS. The display was enhanced the most by the zoanthid and green zoanthid. With so much color I was able to make the tanks look more balanced. Adding a yellow zoanthid in addition to green zoanthid was my favorite because it added more yellow to my reef while providing balance for the yellow porities. Under normal lighting conditions this looked almost actinic yellow and really broke up the purple and blue acropora.

Pink Zoanthids

Pink Zoanthids, Reef Corals
Credit: Blane Perun

Generally imported from the Pacific, the pink zoanthids may also come from the Caribbean and I have several morphs. They act similarly, in regards to lighting, to the blue zoanthids. Pink zoanthids from the Caribbean are more forgiving than those from the Pacific where lighting intensity is concerned.

Pink zoanthids from the pacific are very compact and a great deal of current is necessary to prevent infection from occurring. Without the current the white cotton may take over the colony at any time.

When compared to the blue zoanthids the pink zoanthids retain their color much better and adjust to lighting situations better. Tunze Stream pumps helped me create the right amount of current for my pink zoanthids. This current allowed the pink zoanthids to grow and remain healthy despite in captivity.

When it comes to caring for pink you will not have many problems simply because they are easy to care for. They do require moderate to high light, though, so it is easier to care for them if you provide them with the necessary lighting conditions. They are moderately aggressive and are from the Indo-Pacific. They are from the zoanthidae family and flourish in water conditions of 74 to 80 degrees Fahrenheit and a pH of 8.1 to 8.4.

The hot pink zoanthids are absolutely beautiful and will take the breath away of anyone who views them. Any reef aquarium with hot pink zoanthids will certainly be the envy of the neighborhood. Budding is the method of growth and reproduction for the hot pink zoanthids if they are kept in the proper environment. The opening of each polyp is close to 4-5 mm across and they are a smaller zoanthid species.

When you place the pink zoanthids on the bottom of the aquarium you will want to ensure that it is on rock that is exposed to the currents. Otherwise, the zoanthids won’t be able to get the trace elements and nutrients they need. Each step is fairly easy and overall the pink zoanthids are not difficult to care for. It’s just ensuring that you know what each step is and ensure that it is followed. The pink zoanthids will expand the colony most of the time so don’t crowd them with other coral specimens. Zoanthids will need supplemental feedings on occasion although the zooxanthellae provide them with most of their nutrients.


Palythoa, Reef Corals
Credit: Blane Perun

Palythoa are counted among the most well-known varieties of cnidarians. These are zoanthids from the Anthozoa class, and have the special property of being essentially poisonous. Excreting a toxin known as Palytoxin, the zoanthids are able to defend themselves against predators far more easily than other types of species. Despite being somewhat dangerous for any living creature that approaches them, these cnidarians are quite beautiful as well. Their flowery shapes extend harmoniously on the seabed, beautifully decorating it with stunning gardens of many colors and intricately developed patterns.

Most species of this genus are associated with a distinct set of qualities that sets them apart from most other corals. The relatively small, flower-shaped animals are cnidarians that, together with two other varieties of zoanthids – Zoanthus and Protopalythoa – make up the largest part of the order Zoantharia. These species can commonly be found both in the vicinity of islands and shallower waters surrounding coral reefs, and in the deep ocean, being able to withstand a wide range of marine habitat conditions. Their polyps are partially embedded into the tissue that covers the substrate where the coral colony grows, and most species feature a central disc and a set of tentacles that vary in shape, size and color, depending on the species.

One of the main characteristics of the genus is that these species are able to use a potent toxin known as Palytoxin, in order to immobilize virtually any type of animal. The toxin, known to be dangerous even for humans and other land mammals, is essentially a fatty alcohol, and researchers have shown that even the most minute quantities of it could prove to be fatal, should they be ingested.

Although the “flowery” shapes of these unusual animals are due to the distinct placement and form of their discs and tentacles, that doesn’t diminish their beauty or the intricacy of their unique textures. A rare quality of these zoanthids has to do with their colors. In most cases, they are either cream or coffee color, and they can also be brown, white and yellow. However, in the case of some species – only a few very rare varieties – you will also be able to see fluorescent colors that actually glow in the deeper areas of the ocean, where sunlight is scarce or largely non-existent.

Various species from this genus have been observed in their natural habitats for more than 200 years. In fact, even some of the rare, fluorescent species have been discovered as early as the beginning of the 1800s, and currently there are more than 120 known species that inhabit the oceans of our world. Protopalythoa are lesser known, scientists having focused on researching them far less than on similar genera. According to some researchers, the two genera might be closer related than it was thought in the past and, while further study is necessary, Protopalythoa is believed by some to actually be a part of the Palythoa genus.


Protopalythoa, Reef Corals
Credit: Blane Perun

Protopalythoa corals are among the most colorful, most attractive and most resilient corals. Being a genus that comprises numerous species including sea mats, giant palythoa, button polyps, zoanthids and many others, the members of the group are widespread and quite common in the warm water areas of the Pacific and Indian oceans.

These corals are found in many parts of the Indo-Pacific region. They prefer reef flats and shores covered in rocks in the intertidal zones, where lighting is moderate and currents are mild. Many colonies can be found on the Great Barrier Reef in Australia.

These corals are among the most colorful of them all. They have soft bodies covered in smooth, leathery skin. Many of them are orange, green yellow or brown or are of other dark colors, with many species having brighter-colored elements on or at the end of their tentacles. Some of them have brightly colored tentacles that become fluorescent in blue light. Most members of the genus are quite large corals (the tentacles can reach 2 inches in diameter) that feature a disk-like appearance, with a mouth in the middle and tentacles of various colors extending from the center, in some cases creating a striped appearance. They are known to prefer solitary life, but occasionally they can form small colonies, too. All the corals in the colony are connected by a mat that anchors them to the sea floor.

Some of the species release neurotoxins as a means to protect themselves against predators. The chemical released is called palytoxin and it is so potent that it can be lethal for humans as well. Even so, there are fish species such as filefish, butterflyfish and angelfish and some larger crustaceans that are immune to the toxin and turn to these corals as a source of food and some slugs and snails such as the box snail also feed on the coral species belonging to the genus.

Like most other coral species, they also entertain a symbiotic relationship with zooxanthellae algae that live inside the coral polyps and provide them with the nutrients they need. However, this symbiosis is not their only source of food: these beautiful and often very aggressive corals are also known to supplement their diet by capturing microscopic organisms such as tiny shrimps or plankton from the water column.

Along with most other species, these creatures also proliferate predominantly by spawning, but they are also known to be able to proliferate asexually, by means of budding. Some of the species belonging to the genus are hermaphrodites, having both male and female reproductive organs, while the members of other species are either male or female. During the spawning period, the sperm and the eggs are released into the water to combine and form larvae that start floating freely in the water to find a suitable area for settling. After anchoring itself to the substrate, the larva will start growing into a coral, occasionally forming a new Protopalythoa colony.


Both Zoanthus and Palythoa have chemicals that are not only toxic to reef inhabitants but also to humans. Palytoxin is the most well and has been documented extensively. It is the most poisonous marine toxin that is currently known. (Mereish et al, 1991).This toxin can potentially cause death and have affect on the nerves, muscles, and the heart. Some victims will even be paralyzed. Because of this when you work with zoanthus you will need to be prepared in advance. Some people handle the zoanthus with their bare hands while others choose to use gloves. Whatever you choose, be sure to follow the zoanthus handling tips below to ensure you don’t get sick.

Since there is a danger with zoanthus you will never want to handle it or even the palythoa if you have a wound that is open. You will want to avoid touching your eyes, mouth, or even nose without washing your hands after touching the species. It is of critical importance to remember this when propagating the species. Even a very small amount of the toxin can cause you to go to the hospital so you must take extra care.

In general, zoanthus are peaceful and their growth rate may be slowed by controlling the load of nutrients provided. However, in some cases they can be aggressive towards soft and stony corals.

It may sound scary when you read about the toxin, however don’t let it scare you. I have worked with thousands of zoanthus since the mid ‘90s and only one time had a small experience that caused some nausea and numbness. As the specimen grows you will be more likely to see aggression. This is important to watch out for and something that you might find amazing as it occurs.

It is also amazing that the less color the zoanthus has the faster it will grow. Photosynthesis and absorption are the methods of feeding for zoanthus so the more nutrients and light you have the faster the zoanthus will grow. This can be dangerous when you have to prune the colony through propagation. That is because the toxin is released in a small system rather than a big ocean with currents. Keep this in mind when you are growing zoanthus so you will always know what to expect and how to handle the zoanthus in your aquarium.

Blane Perun

Diver - Photographer - Traveler

Whale in Ocean