You could always Turn the light on at night and off during the day. That way the lights would warm the tank when the ambient temp is cooler. Unless you have live plants don't turn the light on except when you want to look at the fish. Fish don't need that much light, room light is fine, the light is for us or live plants. In a 5 gallon tank the light is most likely warming the water as much or more than the heater. I agree that a larger heater would work better.
The ambient temp in my house during the winter is 55-60 and 50-60 during the coldest months. I have a 100 watt on my 25, 3 sides have blue styrofoam insulation it does well until the room temp drops to 50. I can put the insulation on most of the tanks front or add a 50 watt heater.
Betta do like the warmer water than most other tropical fish, 75-84 is fine for them. Over 78 is to hot for most other freshwater tropical fish. The hotter the water the less oxygen it contains.
The ambient temp in my house during the winter is 55-60 and 50-60 during the coldest months. I have a 100 watt on my 25, 3 sides have blue styrofoam insulation it does well until the room temp drops to 50. I can put the insulation on most of the tanks front or add a 50 watt heater.
Betta do like the warmer water than most other tropical fish, 75-84 is fine for them. Over 78 is to hot for most other freshwater tropical fish. The hotter the water the less oxygen it contains.
