Colossoma brachypomum 10-12cm

Piaractus brachypomus, is a large species of pacu, a relative of piranhas and silver dollars, in the serrasalmid family. It is native to the Amazon Basin in tropical South America, but formerly included populations in the Orinoco, described only in 2019 as a separate species, P. orinoquensis; moreover, P. brachypomus is widely cultivated and has been introduced to other regions. In South Florida it is invasive in rivers, canals, or lakes.

As with many other closely related species, P. brachypomus is often referred to as the red-bellied pacu in relation to juvenile appearance. This has resulted in much confusion about the nature and needs of all species involved, with the reputation and requirements of one often being incorrectly attributed to the others.