The razor-toothed piranhas of the genera Serrasalmus and Pygocentrus are the most ferocious freshwater fish in the world. In reality they seldom attack a human.

• 有着锋利牙齿的水虎鱼是世界上最残忍的淡水鱼类，水虎鱼属于锯脂鲤属和纳氏锯脂鲤属。事实上他们很少攻击人类。