Just noticed this on 1 of 4 zoa colonies in my tank. It's only effecting this seems to be a clear/white cacoon that surrounds an individual polyp and after 3 or 4 days the polyp is gone and it start to effect another polyp. It only gets one polyp at a time?? Not sure it this is zoa pox or some sort of fungal disease. Any suggetions and/or help would be appreciated. Pics were taken shortly after my actinics came on. All the other polyps surrounding the affected one opens up fully and seem happy.