the irregular plural nouns

[nour]

hi,
we all know that there are nouns that don't have any plurals. It is the same in singular and plural. e.g. the word "fish" is a singular and plural noun.

But I found in my son's book that "fish" in the plural becomes "fishes"!

Is this correct? Can anyone help me please?

[Casiopea]

Welcome, nour.

This explanation will help. Click here.

What context in your son's book was the word fishes used?

All the best.