Ecological Risk Screening Summary - Red Piranha (Pygocentrus nattereri) - High Risk

Species that are considered high risk have a well-documented history of invasiveness in at least one location globally, and a high or medium climate match to the contiguous United States.

Pygocentrus nattereri is a species of piranha native to the Amazon, Paraguay-Paraná, and Essequibo river basins in South America, as well as north-coastal rivers in Brazil. P. nattereri is a host of several fish-infecting nematodes with zoonotic potential. This aggressive species of piranha has a medium climate match with the contiguous United States, but would likely face difficulties overwintering in most regions. Numerous P. nattereri specimens have been taken from waterbodies across the contiguous United States, but all populations have failed or been eradicated. These introductions most likely resulted from aquarium releases; approximately half of U.S. states allow for trade and possession of this species by hobbyists. In India, P. nattereri introduction has led to reports of human injury. In Brazil, introductions of P. nattereri and Cichla kelberi (peacock bass) have been associated with disappearance of native species from several water bodies, although the distinct contributions of P. nattereri and C. kelberi to these changes have not been quantified. Given the history of negative impacts of introduction in other parts of the world and the medium climate match to the contiguous United States, the overall risk assessment category for P. nattereri is high.