I have a rock, that have a few fan worms about 1-2 inch wide when they opens, since last year mushroom coral grows on the rock, they grows so quick, so many and so big. They are blocking the tube openings. One of the worm actually left the tube and disappeared. What is the best way to remove these mushroom corals. I tried to crap one off, but in a month, it grows back. I want them gone but not harming these pretty feather duster fanworms. What would you do?