Piaractus

Piaractus is a genus of large serrasalmid from South America, and one of several genera colloquially referred to as "pacu". Species in this genus are commonly called pirapatinga.

The two traditionally recognized species of Piaractus are very similar in appearance and were formerly included in the genus Colossoma, which currently only contains another similar species, the tambaqui (Colossoma macropomum). A third Piaractus was described in 2019 as a new species, which was formerly considered a subpopulation of P. brachypomus.