Piranha species are found in freshwater habitats in South America, where they inhabit rivers and lakes. The Red-bellied Piranha (Pygocentrus nattereri) is the most common and widespread species of Piranha. It is found in the Amazon, Paraguay, and Orinoco basins of South America. More than 20 different Piranha species have been described, but there is some debate over how many of these are distinct species and how many are simply geographic variants of other species.