Heater. For my girlfriends betta

[Fishtankfan]

Hey everybody I need help! My girlfriend has a male beta in a 2.5 gallon tank. Her room is the coldest room in the house and poor Sam (her beta) has freezing water . Now I have a old heater from a five gallon that says to work for 3-15 gallon. It says it has an auto turn off when the water is at the temp needed. Would this work? Or would it fry Sam from being to big of a heater? Any help would be. Wry appreciated. Help poor Sam!

 

[Mumma.of.two]

Heaters with thermostats are fine in smaller tanks. They will switch off when they meet temperature. It might need to be set at a lower setting to get the right temp so a glass thermometer on the opposite side of the tank to keep an eye on it is needed. There is a risk of them malfunctioning and overheating the tank but you run that risk with every heater.

 

[DannyBWell]

With it only being a half gallon bigger of a heater it should be fine just watch and check the temperature to make sure

 

[shellieca]

I have an Aqueon 50w adjustable heater in my 2.5g tank that works perfectly. I keep eye on the temp with an in water thermometer & have the heater horizontally along the bottom of the back glass.

 

[Oohitsae]

It will work fine. Just make sure you get a thermometer in there to keep an eye on temp.
Bettas should have their temp at 78-82, non adjustable heaters normally shut off at 76, but its better than nothing, and close enough to their range that its not a big deal.