Tiny white things growing on back of tank and on glass?

[hds4216]

Hi all - there's a ton of tiny white things with feather-like heads growing on the glass and on the back of the tank. They look exactly like mini feather dusters. Is that what they are? Are they bad or indicative of anything negative? Included is a picture.

 

[EagleEye121]

Spirorbid worms. Harmless. My back glass was covered in them until I scraped them off

 

[Ghrommi]

Spirorbis worms, harmless, I have tons of them.

 

[Hugh Mann]

+1 to the whatchacallsit worms. Have thousands on my back glass. Evidently they are harmless.

 

[John08007]

Vermetid snail, not the greatest thing to have growing in your tank. I have them, so far hasn't caused any problems but I've heard of people nuking their tank to get rid of them. Think they become a problem when they start growing near the base of your corals

 

[hds4216]

Vermetid snail, not the greatest thing to have growing in your tank. I have them, so far hasn't caused any problems but I've heard of people nuking their tank to get rid of them. Think they become a problem when they start growing near the base of your corals

They don't look like vermetid snails to me tbh

 

[ScubaFish802]

They don't look like vermetid snails to me tbh

Spirorbid worms as others said