Acnodon
Catoprion
Colossoma
†Megapiranha
Metynnis
Mylesinus
Myleus
Myloplus
Mylossoma
Ossubtus
Piaractus
Pristobrycon
Pygocentrus
Pygopristis
Serrasalmus
Tometes
Utiaritichthys
The Serrasalmidae (serrasalmids) are a family of characiform fishes, recently elevated to family status. It includes more than 90 species. The name means "serrated salmon family", which refers to the serrated keel running along the belly of these fish. Fish classified as Serrasalmidae are also known by these common names: pacu, piranha, and silver dollar. These common names generally designate differing dental characteristics and feeding habits.[2]
Serrasalmids are medium- to large-sized characiform fishes that reach about 1 m (3.3 ft) long, generally characterized by a deep, laterally compressed body with a series of midventral abdominal spines or scutes, and a long dorsal fin (over 16 rays). Most species also possess an anteriorly directed spine just before the dorsal fin extending from a supraneural bone; exceptions include members of the genera Colossoma, Piaractus, and Mylossoma.[3]
Most serrasalmids have about 60 chromosomes, ranging from 54 to 62.Metynnis has 62 chromosomes, as does Catoprion, Pristobrycon striolatus, and Pygopristis.[4]
Serrasalmids inhabit all major and some minor Atlantic river systems in South America east of the Andes, but have been introduced to other areas.[5] Species range from about 10°N latitude south to about 35°S latitude.[6]
The diets of the various serrasalmid fishes include seeds, fruits, leaves, and various invertebrate and vertebrate prey, as well as fish flesh, scales, and fins. To emphasize the diversity of diets, authors commonly highlight the fruit- and leaf-eating pacus and the highly carnivorous piranhas. Most in the family other than piranhas are primarily herbivorous. In contrast, piranhas have been long believed to be strict carnivores.[4] Many species change diets depending on age and resource availability.[4]