I have had 4 different varieties of Zoas placed throughout the tank. Came home one day and 2 of them looked like this, the next day, the other two. I have looked at night with a red light to see if anything is munching on them and cannot find anything. Wanting to try them again and hoping to solve this problem. I only have 2 clownfish, an emerald crab, and narsissus snails. Thanks!