Seahorse Facts

About the seahorse

There are 47 seahorse species, and together with pipefishes and seadragons they make up the family Syngnathidae. They swim in seas, brackish estuaries and lagoons. Adults range from 1.5 to 35 cm (0.6 to 13.8 in). A seahorse has no scales at all. Instead, segmented bony armor sits under a thin layer of skin.

Seahorses are highly modified pipefish, and scientists think the two groups split during the Late Oligocene. One idea is that new shallow seas, formed by tectonic shifts in the western Pacific, spread seagrass beds where an upright fish could hide. That posture also helps them catch small shrimp from farther away than a pipefish can manage, which may explain why the shape evolved in the first place.

Did you know?

• Hippocampus comes from Ancient Greek words for horse and sea monster.
• The oldest known seahorse fossils come from Slovenia and are about 13 million years old.
• A 2016 study found the seahorse genome evolving faster than any other fish genome examined.