Anyone know what these are

[Mooneye56]

Bought some live rock and these are all over them. Any ideas as to what they are

 

[Lovemyreef2015]

They look like tube worm. Could be vermetid snails. He is a great article on how to tell the difference. I would watch the video too it has some great info.

Vermetid Snail Control and Removal (A Quick Guide)

<span>In an aquatic environment like a simulated ecosystem in an aquarium, many parasites flourish. Some of the most destructive creatures that can be found in a fish tank are vermetid snails. Thus, controlling their growth or eradicating them is an essential move for the health of your...

aquariumstoredepot.com

 

[Lovemyreef2015]

They look like tube worm. Could be vermetid snails. He is a great article on how to tell the difference. I would watch the video too it has some great info.

Vermetid Snail Control and Removal (A Quick Guide)

<span>In an aquatic environment like a simulated ecosystem in an aquarium, many parasites flourish. Some of the most destructive creatures that can be found in a fish tank are vermetid snails. Thus, controlling their growth or eradicating them is an essential move for the health of your...

aquariumstoredepot.com

I can't edit my posts. I want to add the top picture looks more like vermetids but it's hard to tell.

 

[xxkenny90xx]

I'm thinking vermited snails. They are a pest

 

[Seadoc]

I'm thinking vermited snails. They are a pest

+1.
See if they produce some slimy filament. They should also have 2 antenna. They are a pest because the slime they produce can damage corals. Remove them from the base if you have access to them or close the hole with reef glue. The video in an earlier post has lots of nice information about them

 

[Lovemyreef2015]

"These formations are very similar to those built by annelid tube worms, which makes vermetids’ identification difficult to the naked eye." Please make sure you read the article. No need to kill off something that could be beneficial to the tank.

 

[AdamB]

I had these vermetid worms in my old 90 gallon tank.No harm but they multiply 100 fold in a years time and was unsightly to me.. I would assume having several that it could have an affect on calcium /alk..??? No for sure on that.
I used a long tweezer to break them
at stem base and remove to control numbers.