characin (kârˈəsĭn) [key], common name for members of the Characidae, a large and diverse family comprising 700 species of freshwater fishes. The characins are related to the carp and the catfish. They are found in Africa and in tropical America, especially in the Amazon. Most species are active and predacious. Most notorious are the piranhas, or caribes ( Serrasalmus species), with their powerful jaws and razor-sharp triangular teeth, capable of killing humans and cattle. Various small, colorful characin species, called tetras, are used in aquariums. A small characin found in Mexican streams is interesting for the stages of blindness it exhibits: those living deep in caves are eyeless; those found near the entrance have imperfect eyes; and the specimens living in open water have normal eyes. A cross of a blind with a normal specimen produces offspring with varying degrees of eye degeneracy. Characins are classified in the phylum Chordata, class Osteichthyes, order Cypriniformes.