About 10 or 12 years ago when I had my first reef tank I had a large amount of little "jellyfish". I seemed to think they came from little creatures that looked like mini feather dusters, but that was so long ago that my memory only serves me the way that I recognised it then. If I knew what I know now, I think I would have been able to identify the mini feather duster things, and probably come to the conclusion that the "jellyfish weren't coming from them. Who knows! But the "jellyfish" I had only came out after lights off, and they filled the tank probably 1 "jellyfish" per 2-3 cubic inches of water. I remember very clearly that there were a lot of them. I didn't have much for pumps to kill them though, as back in those days all I had was an undergravel filter, and an AquaClear HOB filter.
