I‘ve noticed that species can be a little fussy. It’s frustrating though when you’ve had a good run with a coral then it suddenly starts declining. It always seems to be one you’re fond of too! I had been looking for a red fungia (one of the few LPS I have a thing for), Eventually found one and had it suddenly die in a tank with a dozen other coloured fungia in it, I never did find out what caused it.Yes this was my next idea as well. What’s weird is I have other acros and sos doing just fine. When I initially dipped about 8 months ago, I probably found 100+ on the one colony.