Serrasalminae

Serrasalmus is a genus of freshwater ray-finned fishes belonging to the family Serrasalmidae, which includes the pacus, piranhas and related fishes. They are collectively known as pirambebas; the "typical" piranhas like the piraya piranha are nowadays placed in Pygocentrus. Like all piranhas, Serrasalmus are native to South America.

Pygocentrus is a genus of freshwater ray-finned fishes belonging to the family Serrasalmidae, which includes the pacus, piranhas and related fishes. All species are native to tropical and subtropical South America. All the species are predatory, scavengers and may form large schools. The famous red-bellied piranha, Pygocentrus nattereri, is one of four species in the genus.

Metynnis also commonly known as the silver dollar is a genus of freshwater ray-finned fishes belonging to the family Serrasalmidae, which includes the pacus, piranhas and related fishes. The fishes in this genus are found in tropical and subtropical South America. They are herbivorous or omnivorous, and inhabit a wide range of freshwater habitats, ranging from rivers and streams (both fast- and slow-flowing), to floodplains, flooded forests, lakes, pools and reservoirs. They generally reach in standard length, although a few species may reach up to . The genus contains many of the species know

Megapiranha is an extinct serrasalmid characin fish from the Late Miocene (8–10 million years ago) Ituzaingó Formation of Argentina, described in 2009. The type species is M. paranensis. It is thought to have been about in length and in weight. The holotype consists only of premaxillae and a zigzag tooth row; the rest of its body is unknown. This dentition is reminiscent of both the double-row seen in pacus, and the single row seen in the teeth of modern piranhas, suggesting that M. paranensis is a transitional form. Its bite force is estimated between .

Catoprion is a genus of freshwater ray-finned fishes belonging to the family Serrasalmidae, which includes the pacus, piranhas and related fishes. These fishes are found in tropical South America, including the basins of the Amazon, Essequibo, Orinoco and Paraguay rivers. It was believed to be a monotypic genus until the 2020 description of C. absconditus.

Pygopristis is a monospecific genus of freshwater ray-finned fishes belonging to the family Serrasalmidae, which includes the pacus, piranhas and related fishes.. The only species in the genus is Pygopristis denticulata, also known as the lobetoothed piranha,. This species is a rare South American characiform fish found in the Orinoco River basin, rivers of the northern and eastern Guiana Shield, and tributaries of the lower Amazon River. Like other piranhas, it is found in freshwater, with specimens of this species typically found in acidic clearwater or blackwater environments. Despite their