[Sk8r]

Nix to the butterflies. They'll die. They eat corals for a living. I hate to say it, but your blue tang, with a max size of 18", is not appropriate for a 55. No tang really is: too high an oxygen and space requirement. The tomini tang would be close to possible, but for the health of that fish and your tank, I'd really advise against it: just not enough room. I'd advise holding pat at your YWG, lawnmower, firefish and clowns---maybe a couple of the smallest gobies or blennies who never exceed 2 skinny inches, maybe a small jawfish, maybe a pistol shrimp [tiger variety] for your YWG [take a look at liveaquaria.com]---but watch that shrimp. The coral bandeds are known to take after live fish, particularly as they get larger.