Mr. Fish is the name of two fictional supervillains appearing in American comic books published by Marvel Comics. Both versions are brothers who have gone up against the street-level heroes in New York City.

Maggia is a fictional international crime syndicate appearing in American comic books published by Marvel Comics. The organization exists in Marvel's main shared universe, known as Earth-616, as well as other Marvel universes. Its structure is somewhat similar to the real-world New York Mafia, but the Maggia differs in that it frequently hires supervillains and mad scientists to work for them. Some of the prominent Maggia members are supervillains themselves, such as Hammerhead, Silvermane, Count Nefaria and his daughter Madame Masque. The Maggia has come into conflict with various superheroes, including Spider-Man, Daredevil, the Fantastic Four, the X-Men, and the Avengers.