Our Lined Seahorses (Hippocampus erectus) recently gave birth! A female seahorse deposits hundreds of eggs into a male’s brood pouch, where they are fertilized. The male broods the eggs for about 20 days, providing nutrients for growth and development. The eggs hatch in the pouch and the male gives birth. After the young are released into the water, the male often mates again within hours or days during the breeding season.