I'd have been shocked too, never seen anything like that here. Think it might be illegal to sell them here in the UK, I know glofish are banned anyway.
Might be worth looking and seeing if there are any other mom and pop fish stores near you, and choosing them instead. But I know that it varies a lot by area how much choice you have in that regard. If this is the only store, maybe after a while once you've got to know them a bit, can mention that you weren't happy about being sold these fish and not being informed on what they are, and that they were trading in these fish. It might make them reconsider ordering them in again in the future.
Delicate topic though, I know! Easy to say "Call them up and yell at them, then never shop there again!" but if they're your only local fish store, or the closest one and you might need to get something from them in an emergency, not always a good idea to burn bridges! So you'll know best how you want to handle it.
A 35 gallon is a nice sized tank to start off with! You already avoided the most common beginner mistake of buying a really small tank, thinking a small one is a good beginner tank, only to struggle with water quality. You can do a lot with a 35 gallon, while it's also not overwhelmingly large and hard to maintain. What other fish have you got? Any pics? We love tank pics!