Fishes is the proper
English plural form of "
fish" that
biologists use when speaking about two of more fish
species.
There are over 25,000 fishes in the world (meaning that there are over 25,000 fish species in the world). When speaking of many fish that all are part of the same species, then the word "fish" is used.
There are several million fish in the species Gadus morhua.