Interesting tubed worm?

[Chameleon]

Hey yall,
I've got a bunch of these tubed worms I'm wondering about. They all are thin tubes 2-3mm diameter and stick off the live rock about 1 cm. Out of the end of the tubes are long string like very thin fibers...one per tube about 4-6 inches long(very long). Sometimes when I watch closely the strings which have some particulates stuck to them helping with visualization seem to be ratcheted into the tube at a very slow rate. Any ideas on what I'm dealing with. They are everywhere... Thanks
Regards,
Cham

 

[MableShwartz]

Are they white tubes? I have a few of these as well, best as I can figure they're hitchhikers. They're just worms that throw out "net-like" sticky strings into the water, that like you said just gather particulates and bring them back into feed the worm. I haven't noticed them causing any harm to any of my tank inhabitants so I'm pretty positive they're harmless.

 

[firefightered]

I have some of the same but with red tenicles.