Correct spelling, explanation: the origin of fishes can be found in Germanic languages, in the words fisch and fischen. In English, the word appeared in Old English, in which it had the form fisc. The meaning of the word has always referred to animals living in water and that hasn’t changed. It is worth mentioning that the plural form of fish can be either fish or fishes.

Definition of fishes:
1. noun (plural form) – an animal living in water, covered with scales;
There are various types of fishes in this lake so it attracts plenty of fishermen.
2. verb (singular 3rd form in the Present Simple tense) – to go and catch fishes;
He fishes for tuna every year.
3. verb (singular 3rd form in the Present Simple tense) – to look for something, to search, usually with your fingers;
She fishes for cheap clothes in every shop she walks into.

Other meanings of fishes:
1. Fishes – spelled with a capital letter it is one of the zodiac signs;
According to astrology, Fishes tend to be overprotective and sensitive.
2. Fishes – in slang – some guys;
Those fishes standing over there are known in the area as drug dealers.

Incorrect spelling, explanation: the most basic rule of creating a plural noun in English is to add the -s ending to a singular noun. However, when a singular noun ends in -s, -ss, -sh, -ch, -x, or -z we need to add the -es ending to it when we want to create a plural form. Some English users tend to forget about and that’s why a common mistake is to spell fishes as fishs, which is wrong.