What snails are breeding?

[Bruce60]

I have snails that appear to be breeding. I have times when there are dozens of tiny snails on my glass, especially at night. Hard to get a good image of them on the glass, but here are two images. What species are these? Anything I need to to do except enjoy not having to buy more of these? Thanks!

 

[Hemmdog]

Trochus, they are good.

 

[Bruce60]

Thanks for the reply. I knew they were good snails, just were not sure which of them.