Found these floating in water when inspecting frags

[Marc K]

I found these floating in the water when I was acclimating some SPS frags into my QT. They appear to be able to propel themselves. At first i thought hydroid but the photo looks almost like a feather duster worm outside its tube.

Be great to get some thoughts.

 

[Copingwithpods]

Feather dusters, harmless filter feeders

 

[El_Guapo13]

Feather dusters