Someone obsessed with fish and any under water animals, also call people "fishy" and may even want an a pet that grows in water. This phase may go on for several years, they may even believe they're part fish. People who suffer with the fishaboo phase are commonly named Julia.

Internet persona(s) who happens to follow you and you happen to follow them back and maintain communication with and have a mutual liking for eachother whether it be friendship wise, etc. (Mutuals if more than one mutual)

Someone who has/had a fish phase/likes fish/also a fish activist, like a vegan but only for fish.