Which one: blueberry (large light blue polyps on wide fan) or intense blue very small polyps on slender vertical shaped fan?
I would remove the dead branches, but it's up to you.
Few times a day feeding, any zooplankton that fits the mouthes, small doses frequently, if possible.
The small polyped is prone to be covered by algae (bryopsis in my case), when places in well lit place. The blueberry has bad prognosis, from my experiense: I had never seen it eating, in spite of the big polyps.