I have an 85 gal reef tank thats about 5 years old. I have not added any fish in several years. Everybody was getting along great. I lost my mimic tang last week...no signs of illness. Parameters are all good. I want to add a fish or two. Worried about the dynamics of adding a new fish. Really would like some more color. I have 4 pj cardinals, 1 bengaii cardinal, a pair of clown fish and a foxface. I have a fire shrimp, 3 peppermint shrimp, 4 BTA, various corals, and a CUC of various snails and hermit crabs. Any suggestions?