Yeah, how disappointing. I was never able to keep acans or blastos in with mine. Guess even though "generally" regarded as "mostly reef safe" they are still butterflies in the end.
I feel your pain: my potters angel is doing a huge number of my gorgonians. I'm not looking forward to trying to catch her but when my new FOWLR is cycled she can move in with my butterflies there. Stupid fish! But oh so pretty....... <sigh>