I think you told me what I was doing wrong. My Mother-in-law and I both got some Betta's at separate times. When we bought them, they were in these big vase type things with a plant stuck in it. When I got mine, there were tons of these sitting around the pet store. Because of that, I thought it was fine. I asked a lot of questions before buying it. What kind of food do I need to buy? How often should I change the water? But, the most important thing, I wondered, was if I needed to get a different type of tank to put it in. We had one of those little 5 gallon tanks with the filter in it at home. The guy at the pet store told me that it was fine to leave it in that vase contraption. After my fish died, my Mother-in-law bought hers. She asked the same types of questions. She made sure to ask about the tank issue too. This was in a different pet store, in a different town. They told her the same things they told me. Her fish didn't last long either. I'll have to call my Mother-in-law and tell her about the tank and heat. I know she would really love to get another one. Thank you for the information.