any fish that breeds its young in the mouth. Examples include certain catfishes, cichlids, and cardinal fishes. The male of the sea catfish Galeichthys felis places up to 50 fertilized eggs in its mouth and retains them until they are hatched and the young are two or more weeks old. The cardinal fish Apogon imberbis incubates the eggs in the pharynx. Both the male and female Symphysodon discus take turns mouthing the eggs.