I seem to remember coming across tales and legends of reefers losing zoos, corals, fish, and small children to eunicid worms. They all reported the losses as occurring overnight. They all pretty much had to break their tanks down (and some had to break rocks) to get the worms out....some of which were several feet long and had civil war slugs lodged in their flesh. Could you have one of these worms from hell in your tank, eating your zoos?