Piaractus mesopotamicus
Piaractus mesopotamicus
(small-scaled pacu)
Translate this page with Google
Français Deutsch Español Português Russian Italiano Japanese

Copyright Info
Piaractus mesopotamicus (Holmberg, 1887)

Common name: small-scaled pacu

Taxonomy: available through www.itis.govITIS logo

Identification: H. A. Britski (personal communication) considers Piaractus mesopotamicus one of three valid large pacu species (the others are P. brachypomus and Colossoma macropomum). Commonly used synonyms include Piaractus metrei, Colossoma metrei, and Colossoma mesopotamicus. In his taxonomic review, Machado-Allison (1982) used the name P. metrei (Berg 1895). This, however, is a junior synonym of P. mesopotamicus. At least some, and perhaps all, specimens taken in United States waters and identified as this species may actually have been the closely related Piaractus brachypomus. In addition, Piaractus specimens taken in United States waters have frequently been misidentified as red piranhas Pygocentrus nattereri.

Size: To about 85 cm SL, and reaches 20 kg in weight (Lovshin 1995).

Native Range: Tropical America. Restricted to the La Plata Basin, South America (Machado-Allison 1982), including the Paraguay/Parana rivers.

US auto-generated map Legend USGS Logo
Alaska auto-generated map
Hawaii auto-generated map
Caribbean auto-generated map
Puerto Rico &
Virgin Islands
Guam auto-generated map
Guam Saipan
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences: A single fish (56 cm and 3515 g) was reported as taken in Florida by an angler from a brackish-water canal at Sunshine Parkway bridge near town of Cape Coral, Charlotte Bay drainage, Lee County, on 4 July 1987 (Courtenay, personal communication). A single specimen (identified as Piaractus mesopotamicus) was taken in Oregon from Herbert's Pond near Canyonville, Douglas County, in the Umpqua River drainage on 21 August 1989 (Logan et al. 1996).

Means of Introduction: All records probably represent aquarium releases.

Status: Failed in Florida and Oregon.

Impact of Introduction: Unknown.

Remarks: The Florida specimen, originally reported as a piranha in newspaper accounts, was not preserved. That specimen was apparently destroyed and the fish was later identified as Colossoma metrei (= Piaractus mesopotamicus) based on a photograph (Courtenay, personal communication). Because of the close resemblance with other pacus, that identification should be considered tentative.
Voucher specimens: Oregon (OS 11983).

References: (click for full references)

Courtenay, W.R., Jr. - Florida Atlantic University, Boca Raton, FL.

Lovshin, L.L. 1995. The colossomids. p. 153-159. In C.E. Nash and A.J. Novotny (eds.). World animal science: production of aquatic animals: fishes. Elsevier Science, Amsterdam, The Netherlands.

Machado-Allison, A. 1982. Estudio sobre la subfamilia Serrasalminae (Teleostei, Characidae). Prte 1. Estudio comparado de los juveniles de las "cachamas" de Venezuela (generos Colossoma y Piaractus). Acta Biologica Venezuelica 11(3):1-101.

Other Resources:
FishBase Summary

Author: Leo Nico, and Bill Loftus

Revision Date: 7/10/2012

Peer Review Date: 2/9/2016

Citation Information:
Leo Nico, and Bill Loftus, 2018, Piaractus mesopotamicus (Holmberg, 1887): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=428, Revision Date: 7/10/2012, Peer Review Date: 2/9/2016, Access Date: 1/22/2018

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logoU.S. Department of the Interior | U.S. Geological Survey
URL: https://nas.er.usgs.gov
Page Contact Information: Pam Fuller - NAS Program (pfuller@usgs.gov)
Page Last Modified: Thursday, December 21, 2017


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2018]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [1/22/2018].

Additional information for authors