He's a cutie! Did you know that they will 'flare' thier fins out if you hold a mirror up? They think it is another fish, and this is their display of 'back off, this is my territory!' But don't do it too long (5 mins max) cause it would stress him.
I love bettas! I had a little female in a 10 gal tank with a heater to keep the temp at 75, but I had my mom take care of her while I was away and she decided that the water was too 'hot' and unplugged the heater, the fish died since her tank was across the room from an air conditioner... Ugh. I had specifically told her not to mess with the heater, she had frequently told me it was too hot... I explained to her that bettas come from a tropical climate, and read the temp info from a betta site... she didn't believe me though!
Have fun with you little buddy!