I have a ZZ that i've posted pic on here before and it was beautiful and has gorgeous color about up till 1month ago. He got beat up pretty bad and his scales were torn and everything but he recovered and looked almost exactly as before. Then he got beat up again and now his color is gone. I got rid of that other fish so i dont think it has anthin to do with dominance. I do have black gravel so could that be the cause? He is black now. Almost no color. I feed him good food. I have a mix of pure color enhancer and head enhancer