FreakinReefin
Insert idiot comment
So far the flat worm exit has killed several of my mini brittle stars also, I just hope it doesn't kill my large one. I didn't have anything to do with him, so didn't have much of a choice but to risk it with him in there.
How long have you had it in the water? Do you see flatworms on your rock or substrate? As they die they secrete a slimy string that they stay attached to before they release into the water column. Honestly the best thing to do is start a filter siphon. Siphon water into a net in the sump so it stays continuous and just start collecting them in the net/sock.