As a normal human, the man who would be called Mr. Fish was a thug for the Maggia. He was assigned to heist some special isotopes from a shipment truck. After killing the driver, the man started to unload the isotopes. As he opened one box, to make sure it was the merchandise, he was exposed to radiation. The man fell into the East River, and hours later came up a mutant. It is then that he became Mr. Fish.
Later on, Mr. Fish had a plan to go against the Maggia, but first he needed to establish his own territory. To Mr. Fish's bad luck, Luke Cage was hired to guard a certain company's trucks. Mr. Fish attempted to kill Cage by throwing him off a building but Power Man would survive the fall. Cage grabbed a steel beam protruding from the building and prevents himself from hitting the ground. Cage picks himself up and reaches Mr. Fish and his gang on top of the building. Cage takes out the rest of Mr. Fish's henchmen and destroys his gun blaster during the fight. Mr. Fish displays his awesome strength and picks a steel girder. Mr. Fish charges towards Power Man but Cage dodges the attack and Mr. Fish falls off the building and plunges to his doom.
In a weird twist of fate, Mr. Fish's brother is afflicted by the same fate.
Mr. Fish was created by Bill Mantlo and George Tuska in 1976 and first appeared in Power Man # 29.
Mr. Fish had a small crew of thugs with him, and one stood out more so than the other, Shrike. Shrike was a short, stereotypical, southern, black guy. He was Mr. Fish's right hand, and was fairly agile.
Humbug would communicate with his insects as they try to gather any information on the location of an auction to take place where Ricadonna is selling an important chip. Walrus and Mister Fish are seen at a strip club giving some cash to an obese stripper named Candy who was studying to become an astronaut.
Mr. Fish would reappear years later in New York and come into conflict with the Fantastic Four. The Human Torch would circle around Mr. Fish as he ridiculed his name. The flaming heat from the Torch dehydrates Mr. Fish and then he gets knocked out by one of New York's finest.