ID of some odd snails?

[Formulator]

Two of the latest oddities to show up in my tank. Haven’t seen either of them before. The spiral one was sitting right on top of a large favia brain which looks ticked off now. Pest, I assume?

The bigger dark colored one just has a weird thumbnail looking shell on its back.

Reverse side of the spiral snail:

 

[Tamberav]

The spiral one is just a trap door from a dead snail.


The other looks to be a stomella, good guy.

 

[Formulator]

The spiral one is just a trap door from a dead snail.


The other looks to be a stomella, good guy.

Ahhh, yes the trap door! Obvious now that you mention it. Stomella - glad it is not a pest because I’m pretty sure they are spawning in my tank…. Thanks for your help!