Do fish lay eggs or not?

Most fish species lay eggs, but there are a few exceptions. Some fish species, such as the guppy and platy, give birth to live young. These fish are known as ovoviviparous, which means that the eggs hatch inside the mother's body and the young are born live. Other fish species, such as the sea horse and pipefish, have the male fish carry the eggs in a pouch until they hatch.