It is a member of the family Pimelodidae and is exclusive right from South America to which also belongs the surubíes, although does not reach the same statures. They are fish that rare time surpass the 50 cm and the 1,500 gms. Despite they are very pregivers, and it is fed during the night, of small fish, alive crustaceans and other organisms. It adopts in the nature, a vertical position and head down between the vegetation, being confused between the stems, as a parade rest and of watching, possibly surprising its prey. It is a very quick fish
Its body very elongado and is depressed specially in the head which gives origin to its name. Of gray color in the back and cream in the belly, divided these by a more or less heavy line, of dark color that crosses the body in longiudinal form from behind opérculo to the same fin of great volume. It is a very interesting fish from the acuarismo although it presents difficulties for his reproduction in captivity and requires of great aquariums. In the nature one by the end of reproduces spring and principles of summer.