A fish was caught. We caught a fish. We caught only one fish. A 跟 one 都可以,只有在很少数情况下需要有差别。至于fish 还是 fishes. 要是一种鱼类不论多少条都是fish. 多种鱼类就要用fishes.
比如:一条
黄花鱼,三条黄花鱼 = 1 fish, 3 fish 然而 一条黄花鱼,两条
比目鱼和一条鲨鱼 = 1 fish, 3 fishes
哪个说什么“one piece of fish" "two pieces of fishes" 的人打错,写成了 “一块鱼肉” “两块不同种类的鱼肉”