I got this one about a week ago and it's heads (i can't think of a better word right now haha) have all opened up and taken food more than once. Do the ones in the middle look like they are dead or do they just look like this sometimes?
Is there anything close to that side of it that could be irritating it? The polyps look like mine when my cleaner shrimp has stolen its food. If nothing is picking at it or stinging it, it's probably just hungry. How is the flow? They like pretty good flow.