I think the latest TFH has an article on that very same topic

I'm sure I have come on too strong in pulling a proprietor aside to ask them what was bothering the fish in tank 37. But if somewhat experienced aquarists don't avoid nasty tanks or (if one net is used for every tank) nasty shops even, who is to protect the newer aquarists? It is better to be more tactful than I was initially.

The pet industry will have research suggesting that a regular customer will spend so many $100 every year if they are kept on. Or the shop can get double that out of unprepared newbies (including usually useless medicine used incorrectly) that first year and then the customers will give up fish (cars, dogs, gerbils, whatever) and go away.

Yes, there will always be those customers like the family where the parents demanded the goldfish NOW. If we get into war stories on goofy things fish sellers do, you should hear the war stories some fish sellers tell about customers. One had a return policy and received a big bag of dead angelfish back in the tank water. When she opened the bag, she could was hit by the overwhelming stench of bleach. They had read about cleaning a tank with bleach and had never thought about getting rid of it! (A little knowledge IS a dangerous thing!)

The lady who was in charge of the houseplant department many years ago at an old Dime Store (either a Ben Franklin or FW Woolworth's) noted that the department was carried by the half dozen little old ladies who would buy a plant, kill it off and be back a week or two later for another victim. In the southern suburbs there was a couple who bought fish and tanks and tanks with no regard for how they were going to take care of them in terms of time, space or even finances. When he suffered a complete breakdown and was hospitalized, the wife called us up and asked us to rescue many of the survivors and take them to an auction. When we came in the front door they had eight 3-foot identical white teddy bears. ("What're they going to do, breed them?") They could never say X is enough. Sadly a couple of years later, divorced and broke, he called, looking for the best way to sell the then empty tanks.

I recall a guy who had called me up and asked what kind of peat one put with mummichog. I told him that Fundulus heteroclitus is a brackish water fish and one that you actually put some sea salt in the water (to a hydrometer reading of 1.005 to 1.015) and tried to keep the tank quite alkaline. He called back and still wondered how much peat went with the Mummichogs. I about yelled at him that he would kill them if he insisted in putting peat moss in there and acidifying their water.

In passing, I made the mistake of mentioning a killifish auction about 2.5 hours away in Elkhart which was taking place a week or two later. Sure enough he showed up, bought two 1.5 x 1.5 x 3 foot styro boxes, acted the buying fool, actually found a pair of F. heteroclitus among many other killies, filled the boxes and headed home. I did a little of the auctioning late in the proceedings and "didn't happen to see" his had raised on some of the fish he was still bidding upon.

By the time we got home a mutual acquaintance in the city was leaving frantic messages that there was this guy who wanted to borrow 30-40 tanks and bowls! He didn't even have a tank for any of them! (If I had even known that he had nothing set up, there would have been no mention of any auctions. And I therefore blame myself in part for encouraging him.)

A couple of weeks later he called up and I asked how his mummichogs were. He responded that he had added peat moss to their tank and they still died! I believe that is the only fish caller I ever hung up on.

With luck his offspring will not enter the gene pool. His also couldn't understand why his girl friend looked at that whole mess and didn't stop (figuratively) running until she was far away from him. But it is compulsive folks like that who can't be bothered with reading and checking out what must be done, who collect fish like baseball cards, which encourage shop managers or employees (who may be fired or move on before a year is up anyway) to go for those quick kills. As in politics and government, sometimes the knuckleheads in charge are "our" fault.