funny you should ask about the fighting, as the two largest ones obviously got into it a week ago, both of them have wounds right above their mouths. I'm considering getting rid of the one that isn't as nicely colored. Right now they are in a 55 gallon, two 4 inch males, a smaller male, and a small female. Also 2 firemouths, a 2 inch green terror and a new 3 inch gibbiceps pleco i just bought today. I also have a 55 gallon with a six inch red devil and common pleco. thanks for the feedback