It may be a form of melting. infrequent feeding and ultra low nutrient conditions can lead to entire colony meltdowns. The "cheesing out" syndrome can be the result of limited nutrients (Phosphates, Nitrates). Zoanthids need fish poop, dissolved food matter and the resulting nutrients to thrive.
generally, zoanthids can thrive in the same conditions that SPS corals do. Good dissolved organics levels, high light, good nutrient export, low nutrient byproducts like Nitrates and Phosphates. I am not claiming that Zoanthids need the pristine conditions that SPS corals require but they do thrive in similar conditions. However, I have learned from experience that Phosphate levels below .02 can be detrimental to the health of the polyps. Always remember that Nitrogen and Phosphorus are the building blocks for coral life, so zero Nitrate reading or zero Phosphate reading are not a good thing for your aquarium life.
