nice aquarium. One thing though. Is your mandarin eating prepared foods? They are quite tough to care fore, and unless he is eating prepared foods, needs quite a bit of live rock (at least 100#s) and a mature tank (at least 6 months to get a good microfauna population). He can take 6 months to slowly starve to death, so if he loses size, or does not grow, you may want to find him a better home. But he is very beautiful.