What are these?

[Coral.Reef]

I age seen several similar posts where folks say these are vermetids, however I seriously doubt that. I have had verms before and they are vicious with stringy webs spewed far out. These in contrast are just tubular, with some movement at the mouth. They don’t seem to fan out like a feather duster either. FWIW I do see small orange fan like filter feeders popping out of my rockwork in several places, and that is a good sign. What are these?

 

[tmcca]

vermetid snails looks like. Smash them they will take over tank.

 

[BryanM]

They sure look like vermetids to me. :(

 

[Tahoe61]

I am inclined to say Colonial Hydroids.

 

[tmcca]

I would take out the rock with them and scrape them off with pliers in separate bucket or use bumblebee snails. I had them and took each rock with them took bone cutters and cut them at the base.

 

[tmcca]

Look closely when you take rock out you will see them peaking out those the pest vermetid snails

 

[Staghorn]

Those things love detritus and particulate foods. When you feed the will extend a kind mucous whip to catch the food you should be able to see it

 

[tmcca]

They also probably in your sump, etc. they spawn everywhere :(