Noticed something on my coral

[thisguy1]

Hi lately my coral hasn’t been opening but all my other corals are and I tested my water and everything is fine. The I picked it up to check it out and I noticed these little worm like creatures on it does anyone know what they are?

 

[KJ]

Look like flatworms.

 

[messytank]

It looks more like vermetid snails to me.

 

[Reefkeeper14]

I second the vermetid snails suggestion. A good way to check is if when you feed/at night-time these animals extend a clear-mucus net, then they are probably vermetids