Worms or snail..?

[Anihiel1]

I was re-setting rockwork that fell over, and the back of my largest rock is absolutely infested with tubes of some sort. Under magnication I see no movement but the tubes are covered in fine cilia. Couldn't get a photo under the microscope but hopefully someone will recognize these from the photo below.
What are they, are they detrimental, and if so how do I eradicate them?

 

[Aiptaisia anemone]

Hard to tell but my guess is it’s sponge

 

[Anihiel1]

Really, a sponge? I am absolutely never would have guessed that. Thank you R2R!!!
So should I worry it about it? Is this type invasive or irritating to corals?

 

[BostonReefer300]

Are the tubes hard or soft?

 

[Derrick0580]

If the tubes are hard they are vermatid snails. Get a few bumblebee snails!

 

[Aiptaisia anemone]

Really, a sponge? I am absolutely never would have guessed that. Thank you R2R!!!
So should I worry it about it? Is this type invasive or irritating to corals?

Again kinda hard to tell might need alittle more information like what the person above me is asking if they tube is hard as A shell.

 

[vetteguy53081]

Looks like a colony of digitate Hydroids. You will need to starve them simply by directing water flow towards them, not at them and they will soon starve

 

[Anihiel1]

The tubes are soft, and easily brushed off the rock. I don't see any appendages or antennae emerging. Just the fine filaments they are covered in. If it is hydroids, any way to kill them without killing thorny oysters and turkey leg clams on the same rock? Can't remove it as my qt tank is currently occupied and my other qt is too small for this rock. Would a fw dip do the trick without harm....?

 

[Anihiel1]

I do have several bumblebees but looks like they haven't touched this stuff

 

[BostonReefer300]

The tubes are soft, and easily brushed off the rock. I don't see any appendages or antennae emerging. Just the fine filaments they are covered in. If it is hydroids, any way to kill them without killing thorny oysters and turkey leg clams on the same rock? Can't remove it as my qt tank is currently occupied and my other qt is too small for this rock. Would a fw dip do the trick without harm....?

I've never had digitate hydroids luckily, but I'd take vetteguy's advice. \

 

[Anihiel1]

I've never had digitate hydroids luckily, but I'd take vetteguy's advice. \

Agreed, I was just responding to the earlier question as to whether they were hard or soft