Another treat would be a chromis, damsel, or a cheap shrimp. They provide great nutrition that frozen food doesn't have. Don't get me wrong, frozen food is great, just as long as you keep it varied. Also, live feedings increase aggressive behavior. I usally feed my fish smelt, mysis shrimp, formula 1, and I'm still weening the lion to frozen, but today he devoired the mysis shrimp.
-Mark