The singular form of fish is fish. The plural form of fish is also fish. What are their possessive forms?
- Singular possessives always add -’s.
- Plural possessives add -’s if they don't already end in s.
Because the plural fish does not end in s, it becomes fish’s, just like the singular form.
Note: In some contexts, the plural of fish is fishes. Because that does end in s, it becomes fishes’.