Plural of Jellyfish

What Is the Plural of Jellyfish?

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 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.
The aquarium has five jellyfishes at the moment.

Table of Contents

Are You Good at Plurals?
The Standard Rules for Forming the Plurals
Why Is There Confusion over the Plural of Jellyfish?
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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 scythe	add s	cats scythes
Noun Ending s, sh, ch, x or z	jellyfish dress	add es	jellyfishes dresses
Nouns ending [consonant] o	mango zero tomato	add either s or es (There are no rules for this - you have to know.)	mangoes or mangos zeros tomatoes
Nouns ending [vowel] o	patio ratio	add s	patios ratios
Nouns ending [consonant] y	story penny	change the y to an i and add es	stories pennies
Nouns ending [vowel] y	storey () donkey	add s	storeys donkeys
Nouns ending f or fe	dwarf knife	ves and/or s (There are no rules - you have to know.)	dwarfs knives
Exceptions	goose louse	some nouns undergo a vowel or letters change	geese lice
More exceptions	salmon jellyfish	some nouns do not change at all	salmon jellyfish

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