No Butterflys are "reef safe", but the longnose is the closest they get. I had a racoon in my reef temporarily to take care of some majano anemones, and other than wanting to eat my GOB he was fine. I just put a eggcrate cage around teh GOB and let the racoon eat all the anemones. They will eat your feather dusters too usually. It seems to be really hit or miss with a longnose, some have no problems, and some pick on everything.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety -- Benjamin Franklin