Here’s a question for you: what’s the plural of fish?
English is a pretty convoluted language. Even when things seem straightforward, exceptions pop up to turn regular rules upside down.
Today we'll look closely at the word “fish,” and more importantly, the correct plural use of it.
Whether you're writing a rhyming children's book like One Fish, Two Fish, Red Fish, Blue Fish or a literary novel staged on the sea, understanding the proper use of this word—like all good grammar—can strengthen your writing.
Learn good grammar without depending on tools like Grammarly with bite-sized posts on simple grammar rules like this one.
In general, English pluralization rules are pretty simple: just add an “s.”
My friends and I walked our dogs to the pond, where we saw a few turtles and many fish.
Friend, dog, and turtle all become friends, dogs, and turtles.
And then there’s fish.
The Plural of Fish
An individual fish is just that—a fish. One scaly animal swimming in the sea (or river, or pond, or fishbowl).
Here’s the thing: if you have two scaly animals swimming in your fishbowl, you have two fish. No matter how many fish you have, the word “fish” doesn’t change.
It doesn't matter whether you're talking about a school of fish or the number of fish in that school. The plural form of the word fish is fish.
Its plural form is the same as the singular—most of the time. I say most of the time because this rule sometimes broken and more regular plural forms are also used for some of these words.
The plural for fish isn’t the only case in the English language where the singular and plural nouns are the same word. The plural of moose, for example, is moose. The plural of deer is deer. The plural of sheep is sheep.
Why, then, do we sometimes hear the word “fishes”?
Fish vs. Fishes
Unlike “sheeps” or “mooses,” the word “fishes” is a real, grammatically correct English word. In fact, Merriam-Webster lists both “fish” and “fishes” as plural forms of “fish.”
“Fishes” doesn’t generally come into play in regular conversation, but it’s a helpful term in biology, especially for ichthyologists, the scientists who study fish.
Remember that example from above of the fish in the pond? In general, we’d say we saw fish.
Maybe, though, we saw multiple species of fish. Imagine you're looking at multiple freshwater fishes—some bass, some carp, and some minnows—and want to refer to them as a collective whole. In this case, we could say we saw fishes, because there are several types of fish.
Say it again: you can use the word “fishes” when referring to different kinds of fish.
Fishes: Plural vs. Possessive
There’s one more reason you might hear the word “fishes” tossed around: when it’s used in the possessive form.
To indicate one fish has something, we add an “’s” to the end. For example:
I have one goldfish in a bowl. My fish’s eyes are big.
Note the apostrophe here. It comes before the s because there's just one singular fish.
To indicate that multiple fish have something, though, we have to pull out the “fishes” again:
Sarah has three goldfish in a bowl. Her fishes’ eyes are even bigger.
In this case, we use “fishes’” no matter how many different species of fish there are. The apostrophe comes after the s because there are multiple fish and they all possess something (in this case, even bigger eyes than my fish's eyes).
Fishy Rules of Pluralization
Throughout the history of the English language, we’ve pulled in words from all kinds of different sources and integrated them into regular language. For the most part, we’ve been okay about standardizing things—generally, to make something plural, all you have to do is add an “s” to the end.
Sometimes, though, we mix it up with convoluted exceptions, and then we end up with “moose,” “sheep,” and . . . “fishes.”
What can I say? English grammar is a fishy business.
Have “fish” and “fishes” ever tripped you up? What other convoluted English grammar irregularities do you find interesting? Let me know in the comments.
Two characters are going scuba diving. One is familiar with the correct use of “fish” vs. “fishes,” and the other has never seen a fish in their life. Write their story for fifteen minutes. When you’re done, share your writing in the comments, and remember to leave feedback for your fellow writers!
Alice Sudlow is the Editor-in-Chief of The Write Practice and a Story Grid certified editor. As a developmental editor, she specializes in young adult fiction, though she has edited novels and memoirs of a variety of genres. She also has a keen eye for comma splices, misplaced hyphens, and well-turned sentences, and is known for her eagle-eyed copywriter skills. Find her at alicesudlow.com.