7. Pacu

A relative of piranhas, this fish is native to the Amazon. The pacu eats mostly nuts, and other plants. The scary thing about this guy is his teeth. They look remarkably human. The pacu uses these large teeth to crack open nuts that fall into the water.

This has been introduced into many rivers around the world, eating the native fish out of existence. Some pacu have even been caught in New Jersey and Arizona, where it is believed they were illegally introduced. This is not a fish I want to see on the end of my line.