Hi, I had a Heniochus butterfly and I have about 30 SPS in my 120, it never touched a coral, but got rid of it and one other large fish as the butterfly grew very fast, it was over 5 inches tall. Copperband's are beautiful, you can try it and if it does not work you will have to take it out. Note: my tank is 100% SPS, so the appeal to butterfly may be minimal, not sure what they will do to softies or LPS.