Mister Fish

"No one laughs at Mr. Fish!"

Mort and his lackies

Mortimer "Mort" George Norris
Mister Fish was originally a normal low-level crook. However in one mission, he was exposed to an isotope that turned him into a humanoid fish. He became the leader of the Maggia (an international crime orgazitation) in his area. One of Fish's lackeys, Shrike, destroyed a truck under the proection of the Luke Cage Power Man and accidently led Luke to Mr. Fish when he attempted to flee. Power Man and Mr. Fish fought each other. This eventually ending with Power Man throwing Mort off a building and Mort being killed when he landed on the pavement.

Bill choking Victor Alvarez

William "Bill" Norris
Bill Norris, Mort's brother, took the mantle of Mr. Fish after he somehow (we don't get an origin story) gained similar mutations. Deadly Nightshade formed the villain group Flashmob, which included Norris. They fought the Victor Alvarez Power Man. Mr. Fish knocked out Power Man, but was knocked out himself by Iron Fish. Bill was taken to the prision Riker's Island. According to Mr. Donovan, Mr. Fish escaped the prision. Later, the Flashmob attacked Manhattan, but were defeated by Misty Knight and her version of Heroes for Hire.
Powers / Abilities
Both Mr. Fishes had the same powers. They had super strength. Given their appearance, they may or may not have aquadatic powers. There is no edvience to support this (except their appearance) or deny it. Mort had "an electric zappy gun" (Marvunapp).
References:
http://www.marvunapp.com/Appendix3/mrfishcage.htm (Mort Norris)
http://www.marvunapp.com/Appendix5/mrfishbill.htm (Bill Norris)