The Seahorse (Hippocampus sp.) is a blanket name for over 30 species of small fish named for the shape of their head which looks like a horse. In fact, their scientific genus name, Hippocampus,  is Greek for "bent horse." They propel themselves with their small dorsal fin and adjust their depth by regulating the air in their swim bladder. We can find them in tropical and temperate coastal waters around the world. Data on the different species is vague, but some species are nearing extinction due to pollution and habitat loss. Photo by David Clode on Unsplash.