Sorry blue betta, my computer crashed so I was unable to get on and reccomend a cheap heater for you.
Reyn-I stand by my statement that they are tropical fish that deserve a temperature of what they would live in and is best for their health. Yes they COULD live in colder temps, you could live in a house with a temp of 50 degrees all the time, but it wouldnt be very pleasant. I also still say the temp in the house will fluctuate throughout the day, which is easily fixed with a heater.
Its pretty apparent the commen consensus is that betta tanks should have heaters. It is nice to see most of us on here care enough to spend the money on a small heater for our pets.
Musho-Thats a very good point aswell, heaters arent on for long anyway and cost practically nothing. Also, assuming you lose your heat and not the power, a heater is a life saver.
Sincerely,
Drew