My local pet store (Clark's on Lomas in Albuquerque), where I've bought all my fish and nearly all my supplies, has a 36-hour guarantee. Last fall I went in after a long city bus ride (on a hot bus full of loud high schoolers that wanted to stop every two blocks). I only wanted to buy two simple head-&-taillight tetras to bring my stocking up closer to optimum after one had died. For some reason, I can't recall now, after I described my situation, the young clerk (a young man who had been there a long time -- the store tends to keep its employees), he was iffy about selling them to me. As I was *so* close to a migraine headache already and didn't want to leave empty handed, I said, "Okay, sell me *one* then..." "I will," he said, "but I can't guarantee it." "Fine," I said. I didn't get mad at him because really I understood he cared about even a little $2 fish. Little did either of us know that I then went out to wait for the bus home and the next two busses didn't come; I waited about 45 minutes in the heat for busses that should have come at 20-minute intervals... (I've since thought of alternative ways to get home). The fish survived and may be one of the two I still have in that tank (with two black neons and now two ghost shrimp).
So my suggestion to store employees is to get permission from management to tell ignorant customers that "I'll sell you the fish, yes, but due to what I understand your conditions to be, we cannot offer you a guarantee on them." That may make them think twice if they're about to spend a lot of money. Management might even want to hang up some kind of friendly sign: "Tell us about your aquariums!" in the sneaky attempt to know if the customer is ready for the fish they want...
It might also be nice to have prepared (and paid for by the store of course as a tax write off) a flier on why and how to cycle a tank, and maybe one on what fish should go where, sizes they can get to, compatibility.... A gung-ho store might even offer monthly demonstrations on setting up tanks, with invitations for customers to return daily to see how to do tests, water changes, etc. Both fishy and fishless cycles.
