Snails? Maybe barnacles?

[DaFeesh]

These have been inside a corner in my tank for a few months. They look like baby astrea snails but I haven't seen them grow much. Could they be barnacles?
They don't move, either.

 

[Eagle_Steve]

These have been inside a corner in my tank for a few months. They look like baby astrea snails but I haven't seen them grow much. Could they be barnacles?
They don't move, either.

Spirobid worms. Filter feeders and harmless. You can remove by scraping off if you want.

 

[DaFeesh]

Spirobid worms. Filter feeders and harmless. You can remove by scraping off if you want.

Ok, thank you.