I'd have to agree with CFC, even though I've done this before. Yes, the owners of fish stores should have to know enough about fish to at least tell someone a Goldfish can't be in a bowl, and a CAE might eat your other fish's eyes off, but frankly, when you buy an animal - the responsibility for knowing about its proper care rests on YOU. You can't believe everything you read or hear, but if you take the effort to look up several sites or flip through several books on the the species you are getting, you should be able to come to a general agreement about how an animal is supposed to be cared for. Hearsay and rumor is not enough; you need to do research, because if that animal suffers and dies out of your incompetance, no one can be blamed but yourself. I don't care if the woman in cart with the lazy eye at Wallmart said bettas eat plants. I don't care if Jarek the 16 year old at Petsmart said you can keep 5 goldfish in a 1/2 gallon bowl. I don't care if your uncle's friend's boyfriend said that CAEs are awesome community fish. People tend to be morons; if you haven't figured this out yet, you haven't been living long enough. Always double, triple, quadruple check. This is not the olden days where we are isolated from information and the tools to properly care for animals. You can flip on the internet, go to the library, or sit down with a book and coffee in Barnes and Noble and find out everything you need to know - and probably a lot you don't need to know - about virtually any aspect of aquarium and fish care. Then you can use ebay, aquabid, the internet, and the numerous fish and pet stores around to get everything you could possibily need. You can even buy plants from the country your fish is from, water conditioners that make the water mimic its habitat conditions, and other fish that share a similar ecosystem. These aren't the days of glass bowls and carnival fish!
So yes - though we all make mistakes - the responsibility for our fish lies on ourselves. I think it is perfectly appropriate to gripe about pet stores and wallmart with the hope that one day, management will LISTEN and insist on better training or care sheets. But if you just blindly listened to hearsay or the instructions of someone trained to make money off of you... don't come complaining; you had it coming.