Seahorse is the title given to 54 species of marine fishes in the
genus Hippocampus. "Hippocampus" comes from the Ancient Greek hippos
meaning "horse" and kampos meaning "sea monster".
Seahorses range in size from 0.6 to 14.0 in. They
are named for their equine appearance. Although they are bony fish, they do
not have scales, but rather thin skin stretched over a series of bony
plates, which are arranged in rings throughout their bodies. Each species
has a distinct number of rings. Seahorses swim upright, another
characteristic not shared by their close pipefish relatives, which swim
horizontally. Razorfish are the only other fish that swim vertically like a
seahorse. Unusual among fish, a seahorse has a flexible, well-defined neck.
It also sports a coronet on its head, which is distinct for each
Photo 17, Oct 2010, Boston Aquarium