Biggest I pulled from my 24 was about 7 inches. (That was when the rock was new from store) haven't seen anything like it since, used a cbs to combat them. I've seen a pick where they were over foot long. Can't seem 2 find it now to refrence. I've know about them since 05 when I started.... did the same thing like narkfish, asked questions about them and studied about them a bit. So yes I am sure it was a britle worm I was talking about getting large. My coworkers 12 g tank had so many of them in it they ate a cbs and a arrow crab, he witnesses it both times. Its a coral only tank and doesn't get fed much other then coral additives so I thing the bristle worms did it out of desparation....... his are about 5-6 in long.