Trying to ID

[StevP]

These white things just started growing on my mushroom after about a month. Noticed them real small and all of a sudden they have have really started growing. Any idea what it is and should I get rid of them?

 

[Kamden Uelton]

Feather Duster worms? Do they retract every now and then?

 

[DSC reef]

They look like feather dusters, harmless filter feeders.

 

[StevP]

Feather Duster worms? Do they retract every now and then?

They retract if I touch it.