Ключевые слова: actinopterygii, amazon, america, american, animal, aquarium, bellied, brazil, close, de, fauna, fin, fish, fishes, freshwater, la, life, machado, nattereri, natural, nature, one, paraguay, piranha, plata, pygocentrus, red, rio, river, serrasalmidae, sharp, south, swim, teeth, tropical, underwater, water, wild, wildlife,