What Size Heater Do I Need?

[SeaGoddess]

I am going to breed my bettas in a 10 gallon what size heater do I use?

 

[Noahsfish]

I have a 50 watt in mine.

 

[Blondielovesfish]

The best way to work it out is have one watt per litre and then buy the one nearest to the needed wattage. So you would want a 50 watt heater unless you can get a 40 watt.