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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: Tambaqui

Synonyms and Other Names: Colossoma nigripinne (Cope 1878), C. oculus (Cope 1872); pacu, black pacu, curumim, gamitana, ruelo, cachama.

Taxonomy: available through www.itis.gov

Identification: Machado-Allison (1982) revised the group and provided information for identification. Many synonyms exist; C. oculus and C. nigripinne are junior synonyms commonly used in the aquarium literature and in past reports on United States nonindigenous fishes. Colossoma taken in United States waters also have been misidentified as red piranhas Pygocentrus nattereri or as one of the other pacus: red-bellied pacu Piaractus brachypomus or small-scaled pacu Piaractus mesopotamicus. Species descriptions provided by Machado-Allison (1982) and Britski (1977). For photographs, see Géry (1977, p. 255, misidentified as C. brachypomum = Piaractus brachypomus), Goulding (1980), Machado-Allison (1982), and Araujo-Lima and Goulding (1997). Ruiz-Carus and Davis (2003) presented diagnostic characteristics to distinguish this genus from the similar genus, Piaractus.

Black pacu can be distinguished from other pacus (Piaractus) by the presence of rays in the adipose fin (vs. no rays in Piaractus), lack of a gap between premaxillary tooth rows (vs triangular gap present in Piaractus), and an elongate opercle bone (horizontal width 48-57% of bony postorbital distance vs. horizontal width 40-46% of bony postorbital distance in Piaractus) (Nico et al. 2018).

Size: 90 cm SL and 30 kg (Goulding and Carvalho 1982)

Native Range: Tropical America. Native to the Amazon and Orinoco river basins of South America (Machado-Allison 1982; Araujo-Lima and Goulding 1997).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Colossoma macropomum is the second largest scaled fish in the Amazon River basin. Tambaqui are omnivorous, and possess a unique combination of molariform teeth and elongated gillrakers that allow exploitation of both nuts/seeds and zooplankton as food resources (Goulding and Carvalho 1982). Tambaqui migrate seasonally between whitewater rivers and inundated floodplain forests during low and high water periods, respectively. Spawning occurs in whitewater rivers during the beginning of the high water season, with larval and immature fishes entering floodplain forests and lakes (Goulding and Carvalho 1982).

Means of Introduction: All introductions were probably aquarium releases.

Status: Possibly established in Puerto Rico. Reported, but failed, in California, Florida, Hawaii, Massachusetts, Nebraska, and Texas.

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

Remarks: Pacus are popular as aquarium fish. They are esteemed as food fish in South America, with large fisheries based around seasonal spawning movements and aggregations (Goulding and Carvalho 1982). Most U.S. records represent collections of single fish taken by anglers. The Massachusetts fish was originally reported to be a red-bellied pacu in a newspaper account and as a Colossoma sp. by Cardoza et al. (1993); the fish was later determined to be C. macropomum by W. Fink, based on a photograph of the specimen (Hartel, personal communication). Some specimens previously identified as C. macropomum and taken in Florida waters may very well represent hybrid forms produced by artificial means using Colossoma and Piaractus parents (L.G. Nico, personal observations).

Voucher specimens: California (CAS 76474; SBMNH 1460); Florida (UF 65748, 97061, 119599); Florida (UF 65748, 96235, 97061, 116291, 119599); Mississippi (MMNS 31259); Oregon (OS 13217); Washington (UW 025858).

References: (click for full references)

Araujo-Lima, C., and M. Goulding. 1997. So fruitful a fish: conservation biology of the Amazon's tambaqui. Columbia University Press, New York, NY.

Britski, H. 1977. Sobre o género Colossoma (Pisces-Characidae). Suplemento Ciencia y Cultura, Brasil, 29(7):810.

Brittan, M.R., and G.D. Grossman. 1979. A pacu (Colossoma, family Characidae) caught in the Sacramento River. California Fish and Game 65(3):170-173.

Cardoza, J.E., G.S. Jones, T.W. French, and D.B. Halliwell. 1993. Exotic and translocated vertebrates of Massachusetts, 2nd edition. Fauna of Massachusetts Series 6. Massachusetts Division of Fisheries and Wildlife, Publication 17223-110-200-11/93-C.R, Westborough, MA.

Courtenay, W.R., Jr., and D.A. Hensley. 1979. Survey of introduced non-native fishes. Phase I Report. Introduced exotic fishes in North America: status 1979. Report Submitted to National Fishery Research Laboratory, U.S. Fish and Wildlife Service, Gainesville, FL.

Courtenay, W.R., Jr., H.F. Sahlman, W.W. Miley, II, and D.J. Herrema. 1974. Exotic fishes in fresh and brackish waters of Florida. Biological Conservation 6(4):292-302.

Devick, W.S. 1991. Patterns of introductions of aquatic organisms to Hawaiian freshwater habitats. Pages 189-213 in new directions in research, management and conservation of Hawaiian freshwater stream ecosystems. Proceedings of the 1990 symposium on freshwater stream biology and fisheries management, Division of Aquatic Resources, Hawaii Department of Land and Natural Resources.

Devick, W.S. 1992. The great piranha hunt. Hawaii Fishing News 17(10)6-7.

Géry, J. 1977. Characoids of the world. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Goulding, M. 1980. Fishes of the forest: explorations in Amazonian natural history. University of California Press, Los Angeles, CA.

Goulding, M., and M.L. Carvalho. 1982. Life history and management of the tambaqui (Colossoma macropomum, Characidae): an important Amazonian food fish. Revista Brasileira de Zoologia 1(2):107-133.

Hartel, K. Ichthyology Department, Museum of Comparative Zoology, Harvard University, Cambridge, MA.

Hartel, K.E., D.B. Halliwell, and A.E. Launer. 1996. An annotated working list of the inland fishes of Massachusetts, University of Massachusetts, Cambridge, MA. http://www.mcz.harvard.edu/fish/ma_fam.htm. Page accessed March 5, 1998.

Hill, J.E., and C.E. Cichra. 2005. Eradication of a reproducing population of convict cichlids, Cichlasoma nigrofasciatum (Cichlidae), in north-central Florida. Florida Scientist 68: 65-74.

Howells, R.G., R.L. Benefield, and J.M. Mambretti. 1991. Records of pacus (Colossoma spp.) and piranhas (Serrasalmus spp.) in Texas. Texas Parks and Wildlife, Management Data Series 70, Austin, TX.

Lindsey, S. 2010. Outdoor life: at least if wasn't a piranha. The News Herald. http://www.newsherald.com/articles/tambaqui-85836-doubtful-fish.html. Created on 08/02/2010. Accessed on 08/10/2010.

Logan, D. Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR.

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.

Mundy, B.C. 2005. Checklist of fishes of the Hawiian Archipelago. Bishop Museum Bulletin in Zoology, Number 6.

Nico, L.G., M. Jégu, and M.C. Andrade. 2018. Family Serrasalmidae—piranhas and pacus. Pages 172-195 in van der Sleen, P., and J.S. Albert, eds. Field guide to the fishes of the Amazon, Orinoco, and Guianas. Princeton University Press. Princeton, NJ.

Ross, S.T. 2001. The inland fishes of Mississippi. University Press of Mississippi, Jackson, MS.

Ruiz-Carus, R., and S.B. Davis. 2003. Register of an exceptionally large redbellied pacu, Piaractus brachypomus (Teleostei, Characidae), in east-central Florida, with gonad and diet analyses. Florida Scientist 66(3):184-188.

Other Resources:
US Fish and Wildlife Service Ecological Risk Screening Summary for Colossoma macropomum

Author: Leo Nico, and Matt Neilson

Peer Review Date: 10/22/2013

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.