Fish man was once well a fish and a man. See their was a criminal named the Crazed fish, when the Crazed fish was caught they decided that since he was the crazed fish lets see how he likes it if we combine his DNA with a fishes DNA. Well after they did that he slowly started getting fish characteristics. Their were two of of the so call "Fish Men" until the fish could no longer handle the sudden changes to it's body and died. Fish man became crazed due to the horrors of turning into half fish half man. He was kept in captivity but not for long. About a year after being put in captivity he found his way out the toilet. Yes, not the best way but the one and only way. As soon as he escaped he hid in closets eating people one at a time until he finds the people responsible for his scales and fins. But when he finds them he will not eat them he will take them through the same horror of turning into a "Fish man". That's the story of the "Fish Man"