I think perhaps people are a bit paranoid and jumping to conclusions. I don't see how anybody can make out from that pic that it's a eunicid worm. I've had one before and it looked nothing like the shape in that pic...or the color. From that pic, it looks more like some sort of tube worm...but the pic isn't all that good.
^^^ I would agree, i don't think those are eunicid's and you sure can't tell from that pic. And i don't think your going to see a bunch of Eunicid's hanging out together on the glass with lights on.