Plural of Jellyfish

by Craig Shrives
The Quick Answer
The plural of jellyfish is jellyfish or jellyfishes.
(If you're talking about the number of jellyfish (possibly of the same type), use jellyfish. If you're talking about the number of different types, use jellyfishes.)

The Plural of Jellyfish

The first thing to note about jellyfish is that it is one word, not two. Forming the plural of jellyfish follows the same rules as for fish, which can be fish or fishes. Similarly, the plural of jellyfish is jellyfish or jellyfishes.
  • There are five jellyfish in the tank.
  • (This is correct if there are five of them, either of the same type or different types.)
  • The aquarium has five jellyfishes at the moment.
  • (In this example, there are five different types of jellyfishes. There might be hundreds of jellyfish.)
fish or fishes

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The Standard Rules for Forming the Plurals

The table below shows the standard rules for forming the plurals of nouns in English.
Type Example of Type Forming the Plural Plural
Most Nouns cat
add s cats
Noun Ending s, sh, ch, x or z jellyfish
add es jellyfishes
Nouns ending [consonant] o mango
add either s or es
(There are no rules for this - you have to know.)
mangoes or mangos
Nouns ending [vowel] o patio
add s patios
Nouns ending [consonant] y story
change the y to an i and add es stories
Nouns ending [vowel] y storey ()
add s storeys
Nouns ending f or fe dwarf
ves and/or s
(There are no rules - you have to know.)
Exceptions goose
some nouns undergo a vowel or letters change geese
More exceptions salmon
some nouns do not change at all salmon
Read more about English spelling rules.

Why Is There Confusion over the Plural of Jellyfish?

Confusion arises because people encounter both jellyfish and jellyfishes but fail to recognize the context in which each word is used. Remember that it is the same as for fish.
fish or fishes

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See Also

Plural of fish More about the plural of fish Unusual pluralsPlural forming table Quirks with forming plurals Forming the plurals of abbreviations Forming the plurals of compound nouns

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