The pink fish is a graphical meme within the Doom community. The fish originated with Dave "mewse" Kiddell, who first used it as an avatar on the Doomworld forums. He supposedly found the picture of a fish on a website, although the website itself is unknown. According to him, “Teenage boys generally choose avatars that are drenched in blood and suggest satanism. In order to buck the trend i think i searched for ‘cute anime pictures’”. The fish avatar quickly spread to other people, some of whom created modified versions, such as a green fish, an upside-down fish, and so on.
Mike "Cyb" Watson later created a series of AVI movies entitled “The fish show”. This featured four fish derived from the original pink fish image. The fish communicated by saying the word “booyaka!”, based on a cartoon imitation of Derek "Afterglow" MacDonald saying the word.
The pink fish is sometimes confused with the dopefish, although the two are not related.
The fish has since been identified as a character from the anime Goldfish Warning!