Aquariums often go through an explosion of various critters during their first year or so... they usually die back once whatever nutrient supply is allowing them to breed is consumed.
It sounds like some sort of bristle worm. If they are really tiny, I wouldn't be too worried about them at the moment. How long have they been around? If they've been around for only a short time, I'd give it a bit more time and see if they die back. If you are really concerned about it, an arrow crab in the fuge will likely make short work of them.
BTW... to the other poster who mentioned worms on the glass that fan out at night, search the forums for "Spirorbid Worm."