Feather Dusters in Trouble

Hey everyone. Maybe some remember me and maybe not. It's been a looooong while since I've been here. The truth is, we moved to a new house and I just now was able to put some fish into a tank that's been cycling for nearly a year with a black molly. Anyway, I'm back and hope to meet some new "faces." Hey Tangster, been a while. I hope this post finds you well. Now to my question: Last week I purchased a couple of feather dusters and they were doing well until 2 days ago. Now they won't open and I don't even know if they're alive. Any ideas what could be wrong, is there someplace specific I need to place them, or any other info would be much appreciated.