Fish and Fishes

Fish and Fishes 

Fish is both singular and plural within a species. 


One salmon in a fish, 
three salmons are 3 fish. 


Fishes is the plural when you have more than one species. 


One salmon is a fish, but one salmon and one flounder are 2 
fishes.

plural fish orfisheshelp Fish is the usual plural form. The older form, fishes, can be used to refer to different kinds of fish.