What is on my bubble coral?

[KatieV]

Noticed this guy on my bubble coral today. Comes out of a little hole and retracts back in super quick. Any ideas what is it? Also took a video to show how quick it moves. Thanks in advance!

 

[Crabs McJones]

Looks like a tube worm/fan worm. Harmless filter feeder

 

[Billldg]

Agree with Crabs.

 

[KatieV]

Thanks so much for the feedback! Do fan worms multiply? Should I be concerned at all for the bubble coral?

 

[Billldg]

Not sure if they multiply, I think they do, I wouldn't be concerned as they all work in harmony with each other.

 

[jeffchapok]

They are good filter feeders. I will take all of them I can get.