The red-bellied piranha (Pygocentrus nattereri), also known as the red piranha, is a species of piranha native to South America, found in the Amazon, Paraguay, Paraná and Essequibo basins, as well as the coastal rivers of northeastern Brazil. They are omnivorous foragers and feed on insects, worms, crustaceans, and fish. Red-bellied piranhas often travel in shoals as a predatory defense but rarely exhibit group hunting behavior. Acoustic communication is common and is sometimes exhibited along with aggressive behaviors. They are also often kept as an aquarium species. This fish was photographed at Karlsruhe Zoo in Germany.Photograph credit: H. Zell