Seahorses Sticklebacks and Relatives: Gasterosteiformes

Most sticklebacks, seahorses, and their relatives have a long snout. The mouth usually is very small and has no teeth. These fishes have enlarged protective plates on their bodies. Seahorses and their relatives have extreme camouflage coloring. Many species can change color at will. Most pipefishes and seahorses have no tail fin. Many have a grasping tail like that of a monkey.

Sticklebacks, seahorses, and their relatives live all over the world.

Most pipefishes and seahorses eat small invertebrates (in-VER-teh-brehts), or animals without a backbone, and the larvae (LAR-vee) of other fishes. Larvae are animals in an early stage that must change form before becoming adults.

The larger species eat other fishes. Most sticklebacks, seahorses, and their relatives suck in prey, or animals killed for food, by quickly opening their mouths to produce a strong inward current.

The World Conservation Union (IUCN) lists one species of sticklebacks, seahorses, and their relatives as Critically Endangered and one as Vulnerable. Critically Endangered means facing an extremely high risk of extinction in the wild. Vulnerable means facing a high risk of extinction in the wild. The U.S. Fish and Wildlife Service lists one species as Endangered, or in danger of extinction throughout all or a significant portion of its range.