Micro Feather dusters?

[jw0934]

I have noticed over the past month that I have small little white tubular things growing off some of my live rock. They kind of look like micro feather dusters but dont respond like normal size feather dusters do. i.e. they dont retreat inside if they are suprised by a noisse or light. They are starting to grow on back side of my glass as well. Any ideas what these are? Are they harmful to my tank? How do you get rid of them?

 

[grabbitt]

They are most likely small feather dusters. They are harmless. They won't grow to be much bigger than they are now and they usually sprout up as a result of over-feeding. Again, nothing to worry about

 

[dragonzim]

Can you get a pic of one of them? I have several hundred mini dusters in my tank and they definitely retract if you go near them.