How long have you had the idol and butterfly? Angels will often pick on newcomers and if the angel is large enough, it can do some damage. That said, bot the idol and redfin bf are very poor choices. My sense is both weill be dead soon anyway. The butterfly you selected is an obligate corallivore which in nature feeds exclusively on coral polyps. Unless you can supply it with a diet of coral, or you are the one in a thousand who gets it to eat a variety of prepared foods, it will die. The idol speaks for itself.