+1
They usually aren't good for the system, as they can irritate corals with them slimy strings which they use to feed. and also they multiply like crazy. if you can scrape them from the base (not only braking the top part/tube of them), because the worms are hiding at the end when threatened, and take them out of the water. Or you can dab them with Super glue (gel better) and they will die in them tubes.