What is this?

[Aquavengers]

Just noticed this a few days ago… please help ID it so I can remove it if I need to! this rock has been in the tank since it started about a year ago but I just noticed this tube thing a few days ago and shortly after, I saw whatever it is coming out.

 

[shwareefer]

A tube worm. Protula I think. Just a filter feeder so no harm.

 

[Aquavengers]

I just noticed like 3 more this morning. It’s on top of a patch of GSP, should I be concerned?

TIA!

 

[Labridaedicted]

No reason to be concerned! Its a type of tube worm as mentioned above. Harmless filter feeders that generally don't get out of control.

I would say it's likely a horseshoe worm, probably of the Phoronis genus.