Seahorses Sticklebacks and Relatives: Gasterosteiformes

Sticklebacks, seahorses, and their relatives are active during the day. They live alone, in pairs, in small groups, or in groups as large as thousands. Many species change color according to their background, using this ability to sneak up on prey or to hide from predators (PREH-duh-ters), or animals that hunt and kill other animals for food. Many pipefishes and seahorses appear to hover in one location, controlling their position by coordinated movements of their fins.

Sticklebacks, seahorses, and their relatives are famous for their reproductive behaviors. In some species females carry fertilized (FUR-teh-lyzed) eggs, which are those that have been penetrated by sperm, on the outside of their bodies, protecting them with their fins. In other species the male carries the eggs. Many species use complex courtship dances.