Remember when Mrs. Philopitopidopitus (the old hag with the pointy glasses) taught you that the plural of fish was still fish? It never seemed to make much sense. If you had six guppies, then you have six fish. Right?
Right.
One would then assume that swordtails, guppies, and piranhas (I wonder who will be dinner?) are all fish. Right?
Wrong!
We have all made this incorrect assumption. Actually, you now have three species of fishes.
Confused?
It works like this:
The word fish is both singular and plural. When singular, it refers to two or more specimens of the same species. The plural fishes refers to two or more specimens of different species.
Now go back and tell your teacher she was wrong and make sure that she gives you the two points subtracted from your essay for getting it wrong.
We are the Taleban! Resistance is Futile!