The female sea horse lays her eggs in the male's brood pouch. The male will carry the babies until they hatch, and baby sea horses will cling to one another by their tails to travel together. They are notoriously bad at swimming due to their one tiny fin on their back, resulting in being the slowest moving fish in the world. The female sea horse lays her eggs in the male's brood pouch. The male will carry the babies until they hatch, and baby sea horses will cling to one another by their tails to travel together. They are notoriously bad at swimming due to their one tiny fin on their back, resulting in being the slowest moving fish in the world.