''Piaractus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of large

serrasalmid 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 ...

from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

. 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'').Nico, L.; P. Fuller; and M. Neilson (22 October 2013)
Piaractus brachypomus.
USGS Nonindigenous Aquatic Species Database, Gainesville, FL. Retrieved 2 March 2017. A third ''Piaractus'' was described in 2019 as a new species, but it was formerly considered a subpopulation of ''P. brachypomus''.Escobar, M.D., R.P. Ota, A. Machado-Allison, I.P. Farias and T. Hrbek (2019). A new species of Piaractus (Characiformes: Serrasalmidae) from the Orinoco Basin with a redescription of Piaractus brachypomus. Journal of Fish Biology: -x

Species

There are currently three recognized species in this genus: * ''

Piaractus brachypomus ''Piaractus brachypomus'', the pirapitinga, is a large species of pacu, a close relative of piranhas and silver dollars, in the serrasalmid family.Nico, L.; P. Fuller; and M. Neilson (22 October 2013)Piaractus brachypomus.USGS Nonindigenous Aqua ...

'' ( G. Cuvier, 1818) (Pirapatinga or red-bellied pacu) * ''

Piaractus mesopotamicus ''Piaractus mesopotamicus'', the small-scaled pacu, Paraná River pacu or simply pacu (a name shared with other species), is a South American ray-finned fish that is native to the Paraguay- Paraná River basin,Nico, L.; and B. Loftus (7 October ...

'' (

Holmberg Holmberg is a Swedish surname formed from the words ''holm(e)'' meaning islet and ''berg'' meaning mountain. It is a relatively common name, at least in Sweden, which has to do with the fact that many Swedish place names contain the suffixes ''-holm ...

, 1887) (small-scaled pacu or Paraná River pacu) * '' Piaractus orinoquensis'' Escobar et al., 2019

References

Serrasalmidae Taxa named by Carl H. Eigenmann Fish of South America Ray-finned fish genera {{Characiformes-stub