hitchhiker???

We have these little projections growing on most of our live rock. Is this A problem? If so, what do we do about it? Thanks! OK, I can't post a picture for some reason. The things I'm talking about are hairlike projections, they are single, not in clumps. They're up to about 1 cm in length...

hi. i have just recently noticed an abundance of bristleworms in my tank. we removed them last week when we did a gravel siphon. when we got home from work today we checked the tank and we have now seen all of these critters crawling in and out of holes on our live rock! that are fast moving...