sounds to me like you need to find a new pet store to shop at. if the guy at the store sold you a fish that had white spots on it and then continued to tell you that it was okay, and then the fish soon afterwards died, there are problems there. also, with all those fish dying, you should really consider a qt. i know that it can seem expensive because you basically have to set up a completley new tank, but with those fish dying it would be a good investment in the long run. in my opinion, start a qt and find a new fish store.