hey all, my gsp in a full marine tank has gone on a hunger strike i think this has to do with me adding a new fliter to the tank ever since then his belly has turned black and his flourescent green back has faded to brown. also he refuses to eat anything i put in the tank. any suggestions on what to do? i really have no clue and it's freaking me out i hate to have to watch him shrivel up and die. any advice would be highly appreciated. thanx