My experience with diaseris/plates/etc. frags has been poor at best over the years. They often just slough off tissue and die overnight (looks like this one did the same). The fact that one is smaller than a fingernail probably didn't help either.So when my tank turned on this morning I found that my rainbow diaseris was dead. It wasn't flipped over or anything so I'm guessing that something had to have ate it because it was healthy and looking great last night.