How long do these corals live, and are you blasting the hell out of them with flow? A few of those aren't exactly beginner friendly. But candy canes dying means something is up.I have trouble with acans, candy canes, frog spawn, plating corals (fungia), and had a little trouble with hammers, lost some heads, but the hammers seem to be doing well now.
It 100% has nothing to do with not feeding though. I have no idea what that other dude is talking about.