I wanted to post this thread because yesterday I noticed a large white spot about 2mmx2mm on my Monti Setosa Frag which is really small, half inch at the most. It was finally growing (I just put new lights in) and looking deep neon orange red. I had no idea where the spot came from till this morning. I woke up before lights were on to check out my little fraglet and I could find it... Because it was completely COVERED by an astrea!!!! it was devouring my Setosa!!! I took him off and there is barely any flesh They are also all over my Echinpora which has been struggling for some time. Anyone have a similar experience? I have read that they are harmless but I have also read some species could eat coral. I dont know I have seen them in tanks for the past 5 years and never heard of them eating corals alive!!!