well from what i researched so far, vertimeds arent harmful in small numbers or in areas with no corals, but they can multiply and thus irritating corals with there web, so basically long term , they can kill off a tank by smothering it basically and irritating corals to the point they wont open properly, we alos recently got rid of aspirsa anenomes, im sure i spelt the name wrong, but we injected him with some joe juice, and he never to be seen again, like said removed a zoo eating snail, basically wiped out whole colony to, but theres 14 polyps left, hopefully regen.now to work on this fire worm/spaghetti worm and or vertimeds. probably going to try to plug his hole once we find it with some epoxy putty to kill him off hopefully