Worm in white calcerous tube?

[MarineDream]

I’m struggling to get a picture because it’s so small my phone camera won’t pick it up but maybe someone will know something to look up via my description (as poor as it will be)

Okay so I bought some GSP in on a piece of live rock from an LFS. I noticed three little tubes that are white and look as if they’re made of crushed coral sticking out about a cm from a couple of places in the rock. The tubes are easy to see because the rock is covered in coralline algae. Didn’t know what they were so ignored them but just noticed coming out of one of them a thin hair-like arm which was pulling stuff off of the sand then retracting. Only noticed because the sand was being agitated slightly in a place with little or no water movement.

Any idea what this is? A kind of worm I’m guessing? But good or bad? I’ve been looking up worms but I can’t find any that seem to live in this kind of white rocky tube casing?

Thanks for any help you can give

 

[nanoreefing4fun]

maybe
vermicularis
tube worm - harmless filter feeder...

 

[nanoreefing4fun]

Vermetid snail

 

[MarineDream]

Thanks so much for replying!

It might be that tube worm - though that tube looks a lot smoother than the one I can see but it’s good to know if it is that then it’s harmless! I’ll keep an eye on it.

Thanks again!

 

[nanoreefing4fun]

You are very welcome !