zoa's

Hello not sure what these are growing with my Zoa's i only noticed them when the zoas closed up. It is also growing under a montipora. Images attached. Any help would be appreciated.

Long story short I have a 10 gallon zoa dominated nano with around 30 different varieties from low end to high end and about 6 varieties are suddenly acting unhappy, shriveling up, expelling guts, etc. The kicker is most of the high end varieties look great.. 25 percent of my zoanthid strains...