HomeFish encyclopediaRay-finned fishesCharacinsCharacinsPacu Pacu (Piaractus mesopotamicus) Scientific name: Piaractus mesopotamicus Holmberg, 1887 The Pacu (Piaractus mesopotamicus) is a freshwater fish of the family Characidae. Native range: South America, Paraguay-Paran? River basin. BiologyDark grey to silver dorsally and laterally and white ventrally with a yellow breast.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific namePiaractus mesopotamicusFamilyCharacidae (Characins)OrderCharaciformes (Characins)ClassActinopterygii (Ray-finned fishes)Maximum length40.5EnvironmentFreshwater; demersal; potamodromousClimateSubtropicalDistributionSouth America: Paraguay-Paran? River basin.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesAquaculture: commercialResilienceHigh, minimum population doubling time less than 15 months (Preliminary K or Fecundity.) SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026