'Fish' or 'Fishes'? Which One Is Correct? | Mastering Grammar

(Last Updated: 20 April 2025)

Fish or Fishes: Which One Is Correct?

The usual plural form of fish is fish:

✅ There are many fish in the pond.

✅ I caught several fish yesterday.

✅ We have five fish in our fish tank.

The older form fishes can be used to refer to two or more species of fish. This form is quite rare and is mostly used in scientific contexts:

✅ The seahorse is among the most unusual of all fishes.

✅ Hundreds of fishes are on the list of endangered species.

✅ Professor Lee, who is a fish expert, studies all the fishes of the sea.

The entry for fish in the Oxford Advanced Learner's Dictionary

For example, if a tank contains five goldfish and five guppies, then there are ten fish in the tank, but two fishes (i.e. two species of fish) in the tank.

If you are a visual learner, the following image may help illustrate the difference between fish and fishes.

Finally, fish is uncountable when it refers to the meat of a fish eaten as food:

✅ Many Japanese people like eating raw fish.

✅ The man bought a few ounces of fish for dinner.

✅ We ate a lot of fried fish, roast chicken, garlic prawns, etc.

In summary, the common plural form of fish is still fish, while fishes is technically correct when referring to multiple species of fish. However, using species of fish instead of fishes can help avoid confusion, especially since the latter is less commonly used in modern English.

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Examples from the Media

At the root of the problem is that too many fishermen face incentives to take too many fish out of the water to secure immediate benefits. —The Washington Post (2012)

"When people think of deep sea fishes, the viperfish is one of the first things that comes into their mind," says Yi-Kai Tea, a fish expert from the Australian Museum in Sydney. —The Guardian (2022)

Adults who reported eating fish several times a week when they were children also reported lower success in school, suggesting "that mercury exposure from fish consumption contributes to poor success in school." —Toronto Star (2018)

Recommended Further Reading

'Food' or 'Foods'?
'Noodle' or 'Noodles'?
Pizza: Countable or Uncountable?

Real-World Examples of Misuse

1. Fishermen catch fish. Do not use fishes in this context.
2. Sometimes should be written as a single word.

1. To clarify that the cat's meal occurred before her nap, it is better to use the past perfect had eaten. The past perfect tense is used to indicate a completed action that occurred before another past action. In this case, it helps to highlight the sequence of events: the cat first ate the meal, and then took a nap.
2. The plural of fish is typically fish. Although fishes can be used to refer to multiple species of fish, this usage is rare and is mostly confined to scientific contexts. Based on the context of the sentence, it is unlikely that the reference is to two different species of fish.
(Source: Complete Practice Book for Grammar, Vocabulary & Comprehension, Primary 1)