I have always had a passion for butterflies in my reef. I moved recently and had to "reset" my tank. It was fishless for a few months, which allowed for any residual crypt to die out. Then I stocked with corals first: just soft leathers and SPS. Gave them several weeks to get established. I have since been adding butterflies to make my dream come true. It has only been a few months, but I have a copperband, Pakistani, Yellow Head, Pearlscale and Pyramid in my 180. So far so good. they ignore the leathers (too noxious?) they do pick between the branches of the SPS, but cannot get to the polyps. I am very hopeful that this will work out.
A few things to note: I have NO LPS corals....they would probably be lunch, same with zoos. Also I have introduced no new corals since I started adding fish. Finally, I feed the fish a lot: blackworms or frozen every day, Nori on a clip, and every other day a clam or mussel to munch on during the day. This has the benefit of supplying the corals with the all time best food: fish poop!
So, if you select your livestock carefully it can be done. I would not keep clams or tubeworms, because the butterflies are the whole purpose of the setup. I have stopped thinking about reef safe butterflies and starting planning a butterfly safe reef.
I've got a saddleback butterfly in QT right now! One fish I have always wanted but never kept!:celeb1: