I have noticed lately a white 'fuzzy' worm in my tank or several of them. They look almost like little catepillars. I am not sure what they hitchhiked in on as I haven't made any additions to my tank in the last several months. They seem to be multiplying though. I see them every once in a while but when I feed they come out from the rock in several places.
What are these? Are they a problem and can they take over a tank? I tried to take a pic but did not come out. Would have to catch one and try a pic that way.