What are these things?

[droidus]

I noticed this on my snail's shell, but it's also on my rock.

 

[Hemmdog]

Vermentid snails (spelling?) on a trochus snail.

 

[Crustaceon]

Is that an in-tank algae scrubber?

 

[AC1211]

I noticed this on my snail's shell, but it's also on my rock.

Looks almost like some anemone species.

 

[Swoody]

Yup, as posted above..... vermentid snails.... ughhh I hate these things.... I think mainly because they are about impossible to eradicate !

 

[James M]

I would take the snail out and super glue all the tubes or scape them off

 

[Swoody]

I would take the snail out and super glue all the tubes or scape them off

Absolutely.... scrape them off the snail.... and make sure they land outside of the tank and die a horrible death!!!!

 

[droidus]

Is that an in-tank algae scrubber?

Yup!

Yup, as posted above..... vermentid snails.... ughhh I hate these things.... I think mainly because they are about impossible to eradicate !

Is there any way to do it? I thought about a UV filter.

I would take the snail out and super glue all the tubes or scape them off

Not sure what you mean by "super glue all the tubes". They are also on my live rock

Absolutely.... scrape them off the snail.... and make sure they land outside of the tank and die a horrible death!!!!

Are they harmful to the tank? I think they look disgusting. Would they have to do with the white spots I see? (REF: https://www.reef2reef.com/threads/what-are-these-white-spots.534401/)
Would bumble bee snails help: https://www.liveaquaria.com/product/565/?pcatid=565?

 

[Crustaceon]

Sometimes it’s just better to sacrifice a little portion of the tank glass for algae growth to keep it out of the rest of the display. It’s also hard to make a better pod factory and hiding place. I like it.