I have a redsea golden butterfly in my reef. Similar to my blackback in that it loves things like xenia and green star polyps.
She is a mighty eater of nori, mysis and homemade frozen food, pellets, etc. Well fed. I have never seen her touch any of the five clams, two anemones, nor the sps.
It is rumored that she ate the odd aiptasia however...
YMMV.