(subclass Actinopterygii, order Cypriniformes)
A family of freshwater fish that have a slender body, rather flat belly, low-slung mouth, and single dorsal and adipose fins; the tail fin is strongly forked. Superficially these fish resemble some characid species, but they are distinguished by the absence of teeth in the lower jaw. They occur in tropical S. America.
Subjects: Zoology and Animal Sciences.