Good heater for a 16g?

[OceanCrazy]

I just wanted to know what's a good heater for a 16g. I used one on my 20g freshwater, had the settings all right but it was giving out more heat than it was sopose to and killed 2 fish.

 

[emmett0122]

50 watt heater would be fine. but if the heater was putting off too much heat it was either set to high or i didnt shut off when it should have