Red-bellied piranha, red piranha

These are shy, fearful fish. The species is dangerous to humans only in exceptional circumstances, as for example when large numbers of starving fish are isolated in small basins or backwaters where there is little food. These carnivorous fish play a very useful role in South American rivers. They attack animals that are often wounded or ill and dispose of their carcasses, which would otherwise quickly pollute the habitat as they decomposed. These fish are active in daytime.