hi guys i brought a green mandarine and ever since i got him his been hidding in the back of my tank and has never come out to the front i think his scared to come out, i have a yellow tang a wrasse and a clown none are aggressive, my tang and wrasse are always picking around the tank and ive seen copods in the tank is there a reason y hes doing that ? he has about 2weeks in my tank he getting skinny every day is he going hunger strike hes always in the same location on my right hand side from the tank in the back , also i seen my fish's get near him and not do anything to it.