There used to be a link here to how to ID larger snails based on shell shapes, flat spiral vs pointed, etc. Try searching canaliculata (spelling?) for the links. I think those are related to mystery snails. But I don't recall beyond pomacea genus (search that too). I think some snails are not legal to sell in the US...but that doesn't mean they can't be acquired.
I think, but don't remember for sure, that my pink & purple mysteries had flat shell spirals, not pointy like yours. So maybe you have something else? What size is it? Could it have come on plants as a tiny baby or even eggs?
