If you have a heater, isn't it important to also have an air filter to help circulate the warm water? I just read a post that said bettas do not like air filters because of the current that circuluates through the bowl, so that's why I wonder. In the past few years that I've been caring for my bettas, they each have their "summer" home and "winter" home. In the summer, they get their glass bowls. In the winter, I put them in a heated tank with an air filter. Should I take it out this winter?