About a month ago I bought a nice healthy looking zoanthid (it maybe a paly). Polyps are quite large (about 1/2 inch). The color was dark brownish purple with a lime green florescent mouth. They looked beautiful. Since I have had them in my tank the brownish purple rim has faded and the polyps themselves have sort of drooped. What could be wrong? I have moved it around the tank looking for the right light and flow but nothing seems to work. What should I do? Thanks