千万不要在这条河里游泳，河里到处都是饥饿的食人鱼。

Never swim in this river, it's full of hungry ___piranhas.

那些贪婪的高利贷者就像食人鱼一样无情地剥削穷人。

Those greedy loan sharks act like ___piranhas, ruthlessly exploiting the poor.