Piranhas are indigenous to the Amazon basin, in the Orinoco, in rivers of the Guianas, in the Paraguay–Paraná, and the São Francisco River systems, but there are major differences in the species richness. ... Piranhas have also been discovered in the Kaptai Lake in southeast Bangladesh.

Do piranhas attack humans?

Though piranhas have a reputation for attacking, there's not much evidence to support the legend. ... Black piranhas and red-bellied piranhas are considered the most dangerous and aggressive toward humans. Nonetheless, South American swimmers typically emerge from piranha-infested waters without loss of flesh.

Are there real piranhas?

Piranhas are South American fish with razor-sharp teeth and a reputation for feeding frenzies. ... Two species, Pygocentrus and Serrasalmus, are popular as aquarium fish, according to Piranha-Info. The most commonly known species is Pygocentrus natterei, the red-bellied piranha.