For some reason every frag of zoanthids has 1 or 2 heads closed up and not opening. They were fine and then all of a sudden they shut and haven't opened back up.did a water change to see if that was it. Still no results. Only other thing I've added we're a couple nesarius snails and 10 red leg hermits. This is all in a 144 gallon half cylinder. Really bugging me because each frag like I said has a closed up zoa.all my other corals are doing great