Is the Plural ‘Fish’ or ‘Fishes’?

In the animal kingdom, tacking on an “-s” doesn’t necessarily make a term plural. While the plural of “dog” is “dogs,” the plural of “mouse” is “mice, and the plural of “moose” is just “moose.” So what’s the protocol when it comes to more than one fish — should it be written as “fishes” or just “fish”? Well, the answer is a bit complex, as both are correct terms with slightly different meanings.

If you’re talking about multiple examples of a single fish species, the correct plural is just “fish.” Imagine, for instance, that you have a fish tank filled with only goldfish. You’d say, “I have a tank full of fish.” The same goes if you’re fishing and catch lots of bass — and only bass. It’d be proper to exclaim, “I caught tons of fish yesterday.” You could also refer to a large number of the same species as “schools of fish,” with “school” being the collective noun for groups of fish.

Merriam-Webster does accept “fishes” as an acceptable plural, but that’s not how “fishes” was originally intended to be used. The proper use of “fishes” is for when you’re discussing more than one fish species. For example, it’s more appropriate to say “all the fishes in the sea” instead of “all the fish in the sea” if you’re referring to the many species one can find in the ocean. Or if you went fishing and caught both trout and bass, you should say, “I caught lots of fishes today.” Of course, nobody would really bat an eye if you used “fish” to refer to multiple species. But traditionally, “fishes” is more accurate.

“Fishes” is also used as the present tense of the verb “to fish.” You could say, “He always fishes early on Saturday mornings.”

But for the plural noun form, using either “fish” or “fishes” isn’t likely to offend whomever you’re speaking with. Both will almost certainly make sense to everyone within earshot, unless you’re talking to a piscine perfectionist. Just keep in mind that in general, it’s traditional to use “fish” if you’re describing one species, and “fishes” when discussing multiple species.