My betta is housed in a 1.5 gallon filtered aquarium. I was told a while back when he was sick [though he recovered and is completely fine now] I should get a heater because of how warm their water needs to be. I live in Florida, where the temperature is relatively in the high 70's to the low 80's almost all the time.
His tank is usually around the 80 degree mark at room temperature. My house is the warmest in the house.
Wouldn't getting a heater for him just fry him?
Here is a picture of his tank that I am using. Though this was taken quite a while back. Setup is still the same.