uh. colors come naturally. make sure your tank is getting some indirect sunlight. uh if you have a blue of black background that can help. colored rocks maybe, but they arent necessary. basically, good water, quality diet, good temperature, and some natural lighting will do the trick. if u want really vibrant colors for show get some lighting. also, what kind of shrimp do u feed him and how often do you feed him shrimp? is it raw shrimp or cooked shrimp?? also, do you pre-soak all the food you feed him? i read somewhere that its necessary to pre-soak food so that the fish doesnt get bloated or get digestion problems.