I'd say a Brotia herculea, as they aren't too uncommon, basically an mts that gets to around 10cm long .
Though tbh there's probably alot species out there this guy could be, I find it hard to id snails beyond genus because often separate populations from different tanks have slightly different shell shapes/colours. Mts are a good example .
Would be cool to have a tank full of these instead of mts, where'd you pick him up from?
In that case it's almost certainly Pleurocera canaliculatum, another very variable snail, at least one aquarium site even seems to be selling it . (edit: and this aquarium site appears to have an bay shop, so you possibly got it off them! Living aquatic.
No idea about it's breeding though without spending money on scientific papers.
Yeah, that looks like it all right. And you're also right in that that's probably the shop I got them from. It's too bad I can't find any breeding information on them though. Although I've seen some eggs on the glass today that I've never seen before - that could be them.
The aforementioned eggs turned out to be Nerite eggs. I did however find a young one crawling on my glass today, but couldn't spot any more. I'm still not sure how they reproduce, but I'm beginning to believe it might be seasonal.
It's possible it's a livebearer, even a seasonal one, like Trapdoor snails.
I'm not sure if the seller would know anything about breeding them, since most US-native vendors simply pull their livestock out of a nearby river/creek/whatever and don't breed their own stock.