i have not decided what kind of heater yet. i have been eying this one: <a href="http://www.amazon.com/Deep-Blue-Bett..._petsupplies_3">http://www.amazon.com/Deep-Blue-Bett..._petsupplies_3</a> but I am wary of any product other than food he is specifically marketed for bettas (since that usually equates to too small or inferior quality. if anyone has experience with these, please let me know if they will work for my project.