Uh I don't know much about this saltwater thing..... but we have 2 PJ cardinals, one tru percula, a rose tip anemone, an assortment of mushrooms, a brittle starfish, a scooter blenny, hermits, snails, and LR. I was thinking about getting an about 2 inch long singapore angelfish, will it be compatible with my tank? It is 55gal. Thanks in advance.