8 - Piranha
Of all the fish in all the world's waters, the piranha may have the worst reputation. One look at this predator's slicing teeth and powerful jaws is enough to send chills up the spine. Known worldwide for its aggressive predatory feeding behavior, the piranha is found throughout the fresh waters of South America. They typically feed at dawn and dusk, lurking in the water and waiting for a small animal to pass by. Then, without warning, they attack and devour their prey with ferocity unparalleled in freshwater communities. In some cases, they will form hunting groups in order to take down much larger prey, including horses, capybaras or even humans.