Well, 2 of them at least. We started just over two weeks ago with a new fishbowl, and 3 fish. My boys wanted tropical fish, but I redirected them to more common goldfish-type varieties. It was a very cheap fishbowl with no airfilter and no heater, and the labels on the tropical fish said they prefer a water temperature over 26 degrees C. As we do not normally keep our home that warm in the winter, I was concerned about my ability to keep the water a comfortable temperature, so we bought some fantails. They all died in less than a week.
The following Sunday (a week ago today) we tried again. So far, so good. Of 3 more that we bought, 2 of them are still alive. This is my small victory for the day.