Fish --> Fishes?

English plural forms tend to be pretty simple, in most cases. 

 

You usually add s/es/ies in the end of the word and your job is done.

 

Examples:

 

kid -> kids

 

box -> boxes

 

baby -> babies

 

 

However, some words change differently.

 

Examples:

 

child -> children

 

man -> men

 

woman -> women

 

person -> people

 

mouse -> mice

 

foot -> feet

 

fish -> fish

 

sheep -> sheep

 

datum -> data

 

bacterium -> bacteria