You said earlier that you were going to use a 50 watt heater. If you want to fry your fish you can, (LoL) but I'm hoping you don't want to, so I would suggest at the most a 25 watt heater.
BTW, 50 watt heaters are intended for 10 gallons.
I didn't get a heater since guy at store said for a beta in a 3 gallon eclipse dont need and should be ok.
Also 50 watt seems to be the smallest heater you can get from the 3 stores I looked at so might be something I have to get online since I want a submersable one.
Ok got a few more. Cant seem to get him to spread al of his fins. he is pretty calm when I am around and will come right up to the glass when i am taking pics and just sit there.