
Thankfully the guy working the pet department was young (probably in high school) and listened to me when I explained to him that snails cannot be housed that way. He paged his manager and I explained basic snail care to him as well. When I left the snails that were still alive were put into the plant tank.
The manager's excuse for not having them in there to begin with was that he thought they ate plants. Which I guess is an understandable misconcepting seeing that there are types of apple snails that eat plants and regular folks don't know the difference between them. But now he knows, hopefully they'll put the snails in there from now on.