^ I've seen this video, either in the description or in the comments he states that he found out that it was a fire worm, not a bristleworm. BIG difference.
As far as size, I'm pretty sure I've seen a thread somewhere on the net of a guy with a worm like 5' in length, I don't remember if that's a bristleworm or not. In my 14G I had one that was easily 1ft+ when stretched out, needless to say I removed him