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[when?]

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.

[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.

[4] The primarily carnivorous piranha group comprises the genera Catoprion, Pristobrycon, Pygocentrus, Pygopristis and Serrasalmus, but based on phylogeny also the mainly herbivorous (although with omnivorous tendencies) Metynnis.

Mylesinus, Myleus, Ossubtus, Tometes and Utiaritichthys are found in fast-flowing sections of rivers, and mainly feed on aquatic plants, especially Podostemaceae.

[4] Many serrasalmids are in demand as aquarium ornamentals, and several pacus, such as Piaractus and Colossoma, are economically important to commercial fisheries and aquaculture.

[6] However, piranhas are a considerable nuisance to commercial and sport fishers because they steal bait, mutilate catch, damage nets and other gear, and may bite when handled.