Seahorses and pipefishes belong to the family of fish called Syngnathidae. The family is a very large one – the subfamily of seahorses comprises more than 50 species and the subfamily of pipefishes is equally wide and diverse.
The name of the family is of Greek origin and it is composed of two words, syn that means “fused” and gnathus that means “jaw”, the fused jaw being a feature shared by all member species. Both seahorses and pipefishes are small, usually ranging in length between 1.5 cm and 40 cm. Many of them are able to change color, blending into their environment almost perfectly, using their camouflage to hide from predators and to catch prey. Members of the family share other physical features as well, such as the elongated snouts, the lack of pelvic fins and the thick, plated shell called a dermoskeleton their bodies are covered in. Their shell being thick and rigid, Syngnathidae are unable to swim in the traditional sense of the word – they propel themselves moving their tiny dorsal fins rapidly and advancing belly first. This way of movement might not seem very effective, and Syngnathidae are quite slow, indeed, but they are able to move with precision and to hover over one place for a long time.
Seahorses and pipefish prefer calm and shallow waters. They live predominantly in marine habitats, though there are a few pipefish species that live in freshwater habitats. and there is evidence that there was at least one seahorse that lived in freshwater, too (unfortunately, this species is now extinct). Syngnathidae are found in seas and oceans all over the world, being able to survive wherever they find sufficient food and shelter.
Seahorses are known to be both herbivores and carnivores, feeding on the plants and on other small species and fish larvae available in their habitat, while pipefishes are carnivorous, feeding on the small crustaceans, other invertebrates and small fish that swim by. The species that can change color use their camouflaging ability to ambush their prey – they swim very close to the victim, then they make a thrust to capture it from very close.
Both pipefishes and seahorses leave the duty of taking care of their young to the male. Males have a special pouch on their body into which the female deposits her eggs, usually several thousand of them at a time, and the male then fertilizes the eggs by releasing its sperm into them directly. The fertilized eggs are carried by the male until the young are fully developed, then he releases them into the water and stops caring for them in any way afterwards. Though only less than 0.5% of the young seahorses and pipefishes make it to adulthood, this survival rate is actually much higher than in the case of fish species that release their eggs into the water and abandon their offspring immediately after the eggs are fertilized.