Pacu is a name used to refer to many species of freshwater fish related Piranha, particularily from the family Characidae, and the sub family Serrasalminae. All species are omnivorous. This species is much larger than the common Piranha, some species growing up to 1 meter in length, and weighing up to 60 pounds. This fish is notable because of it's square, human like teeth. Attack victims report, it felt and looked like a bite from another person.
This fish lives in several areas in the US because of introduction, but lives naturally in the Amazon River.