Red Bellied piranha, widely distributed throughout the Amazon River Basin in South America, get their name from the red color on their undersides. They are omnivores who feed on diverse foods which may include fish, plants, aquatic invertebrates, insects, and terrestrial vertebrates. They will also scavenge, feeding on dead or decaying fishes, birds, or mammals. They have earned a fierce reputation because they are capable of inflicting serious bites and even slicing through bone. They are most dangerous when they are threatened or very hungry, this often occurs in the dry season when the water level is low and prey is scarce. Piranha typically swim in shoals of 30 or more, which is helpful for hunting as well as protection from predators. Red piranhas are doing well as a species, but their habitat is continually threatened by development. Removal of rainforests results in siltation and fertilizer runoff from agriculture into waterways, both of which decrease water quality.