I have a juv. Chevron tang in my 120 reef setup. I've had the tank setup for a little over a year now. I also have a purple tang and a pair of black ice clowns. They've been together for 5 to 6 months now and all doing well. Eating mysis krill algae and ageis flake. But it seems in the last month the Chevron who is 2-3 inches lost its beautiful color and is mostly dark all day. Any suggestions maybe something I'm doing wrong? Doesn't seem like the purple bothers him there always fine together.