Fish vs Fishes: What is the Plural of Fish?

Confused about the correct plural of fish? Learn the difference between “fish” and “fishes,” with clear rules, examples, and usage tips.

You’ve probably wondered at some point; is the plural of fish just fish? Or is it fishes? Both are correct. But not always. The choice between them depends on context, tradition, and sometimes science.

This small detail in English grammar often confuses learners and even native speakers. After all, some words only ever use one plural form. You don’t say sheeps or deers. But with fish, you suddenly face two options. So, which one should you choose, fish or fishes? Let’s dive in (if you pardon the pun).

When to Use Fish vs Fishes

Most of the time, fish is both singular and plural. You can say: “I caught one fish.” You can also say: “I caught ten fish.” That feels natural, right? It’s the everyday form you’ll hear in conversation, in recipes, and in casual writing.

The word fish belongs to a group of irregular nouns. Some of them keep the same form in plural like sheep and deer. This is why you don’t hear people say fishes when they’re just talking about dinner or fish in general. If you’re at the market, you’ll ask for “two fish,” not “two fishes.”

But wait. If that’s the case, then why does fishes even exist?

When Fishes Becomes Correct

The word fishes is real, and it isn’t wrong. But it usually appears in more specific contexts. The main rule? You use fishes when you’re referring to different species, not just different individuals.

For example: “The coral reef is home to many fishes.”

Here, you don’t mean a bunch of identical fish. You mean several kinds of fish; clownfish, parrotfish, angelfish, and so on.

Scientists often use fishes in this sense. Marine biologists, ichthyologists, and environmental researchers lean on the term when writing about biodiversity.

So, in short: fish usually means individual animals, while fishes points to multiple species.

Everyday Examples: Fish vs Fishes in Use

Let’s run through some examples.

• “She bought three fresh fish at the market.” (Individual count, same type.)
• “The ocean has many fishes.” (Different species.)
• “The fisherman showed me his fish.” (Plural, casual, no species distinction.)
• “The scientist studies tropical fishes.” (Scientific, species-focused.)

Notice how the choice changes the tone. Fish feels casual, simple, and familiar. Fishes feels formal, precise, maybe even a little technical.

A Quick Historical Detour

Here’s something interesting. In older English, both fish and fishes appeared more freely. Writers didn’t always make a strict distinction. Over time, everyday use favored fish. That’s why you’ll hear it almost everywhere now.

But fishes never disappeared completely. It survived in academic writing and in certain poetic or religious contexts. For instance, some Bible translations use fishes. The Gospel story of the “loaves and fishes” is a famous example.

You might even find fishes in older literature. Authors sometimes preferred it for rhythm or style.

So, while fishes may feel unusual to modern ears, it carries history and nuance.

Why the Distinction Matters

Now, you might be thinking: does this distinction really matter? Can’t you just use fish for everything? Well, yes and no.

If you’re speaking casually, most people won’t notice. Saying “The lake has many fish” is perfectly fine. But in contexts where species diversity matters, the difference matters too. Imagine a scientific report. “The river contains many fish” could sound vague. Does that mean a lot of one species, or many different species? That’s where fishes saves the day.

So, the choice is not about grammar alone. It’s also about clarity.

Fish in Idioms and Expressions

English is full of idioms, and especially idioms with the word fish. And here’s the thing, you rarely see fishes in them.

• “There are plenty of fish in the sea.”
• “A big fish in a small pond.”
• “Like a fish out of water.”
• “Something smells fishy.”

In idioms, the language tends to freeze in a certain form. And that frozen form is almost always fish. You’d never say “plenty of fishes in the sea” in casual speech, even though it would technically make sense.

This shows you how culture and habit shape grammar. Sometimes the “rules” bend around what people actually say.

Fish in Science and Nature

Here’s where things get more formal. Scientists who study aquatic life often use fishes. It allows them to talk about groups of species without confusion.

For example: “The Amazon River hosts more than 2,200 fishes.” That doesn’t mean 2,200 animals. It means 2,200 distinct species.

The scientific community needs that precision. When you’re cataloging biodiversity, every term counts.

In everyday life, though, you’re not counting species.

Cultural and Religious References

As mentioned earlier, fishes has a place in certain cultural and religious texts. The “five loaves and two fishes” story is still quoted often. Some translations of Shakespeare also use fishes.

So, when you come across fishes in these contexts, it isn’t a mistake. It’s tradition.

Interestingly, those old uses often stick around because of repetition. Once a phrase gets fixed in cultural memory, it resists change.

Fish as an Uncountable Noun

Here’s another twist. Sometimes, you don’t use fish to count individuals at all. Instead, you use it as an uncountable noun, like water or bread.

For example:

• “Do you eat fish?”
• “This soup tastes of fish.”

In these cases, you’re talking about fish as food or material, not animals. And when it’s uncountable, you never pluralize it. Nobody says “fishes soup.”

This adds another layer of flexibility. The word fish can be countable or uncountable, depending on context.

Grammar Rules in Action

1. Use “fish” for singular and plural when counting animals.
   Example: “He caught five fish.”
2. Use “fishes” when referring to multiple species.
   Example: “The Amazon River has many fishes.”
3. Use “fish” when referring to food.
   Example: “We had fish for lunch.”
4. Use “fish” in idioms.
   Example: “There are plenty of fish in the sea.”

What You Should Use in Writing

So, if you’re writing something right now, what should you do?

• Use fish as the standard plural.
• Use fishes only if you’re discussing species, science, or quoting tradition.

This guideline will keep your writing clear and natural. Overusing fishes can sound strange, even pretentious. But avoiding it entirely could cause confusion in technical contexts.

Common Mistakes to Avoid

Here are some pitfalls to watch out for:

1. Using fishes casually when fish is expected. Example: “I bought two fishes for dinner.” That sounds odd.
2. Forgetting the species distinction in academic writing. Scientists won’t forgive a sloppy fish when you meant fishes.
3. Assuming one form is “wrong.” Both forms exist. The trick is knowing when to use each.

A Closer Look at Other Irregular Plurals

It might help to compare fish with other irregular nouns.

• Sheep stays the same in singular and plural.
• Deer does too.
• But person becomes people, which is completely different.

So English has no single pattern for irregular plurals. The choice between fish and fishes might seem odd, but it’s not unique. It’s part of a larger family of irregular forms.

Summary of Key Points

• Use “fish” for most situations.
• Use “fishes” when referring to multiple species.
• Never use “fishes” when talking about food.
• Idioms always use “fish.”
• Context decides the form.

Situation	Correct Form	Example
One animal	Fish	I saw a fish.
Many animals (same)	Fish	I caught five fish.
Many species	Fishes	The sea holds many fishes.
Food	Fish	We ate fish for dinner.
Idioms	Fish	Plenty of fish in the sea.

Final Thoughts

So, what’s the plural of fish? The short answer is fish. The longer answer is fish and fishes, depending on what you mean.

You’ll use “fish” in most situations. You use “fishes” only when talking about different species. If you keep that rule of thumb in mind, you’ll never go wrong.

With this knowledge, you can write and speak with confidence. Next time you see the words, you will know exactly which one to use.