Piranhas are also one of the a invasive species. They would eat just about everything in sight. They even eat people in one bite! You would never I mean never get close to even one. Most of them swim in groups of 40,000! Piranhas. Their teeth are the #1 sharpest in the world. They look like regular fish BUT THEY ARE NOT! They can really, really, really hurt you when you get close to them!!!