fish是可数名词吗吗

There are about 30 000 species of fish in the world.

世界上约有3万种鱼。

Fishing is good at high water.

高水位有利于钓鱼。

How can you tell what sex a fish is?

你怎样辨别一条鱼的雌雄？

I don't like fish.

我不喜欢鱼。

You need a licence to fish in this river.

你在这条河里钓鱼要有许可证。