How To Warm Up Water For Betta Fish. Direct an electric fans airflow towards the surface of your betta fish. Make sure that you purchase a heater that is suited for the volume of your betta fishs tank.
Move your tank away from windows and into warmer areas of the house. Add hot water to a bag and float it in your tank. Heating the room and keeping it warm with central heating or a smaller unit.
All you have to do is use regular tap water then adjust the pH level of the water to get it as close to 70 neutral as you can.
When doing particial water changes its good to have the new water as close to the temp as the tank wateryou can do this by taking the aquarium heater and using it to heat up the new wateror you can run the hot water faucet till it is more or less the temp of the tank wateradd conditoner then add the heated. The temperature will increase in the Betta fish tank for about two minutes then it will begin to decrease. Betta prefers warmer water than cold water. Block any sunlight that may shine on your tank.