My betta just died after i moved him to a new tank. I think he didn't like the air bubbler because it created a current around the tank. Idk much about this stuff... i just know that moving fish to a new tank is tricky business.

I would say you're feeding him too much, but if you've kept him that way for a year already then I'm not really sure. I've seen a betta that was fed everyday (they will eat and eat until they make themselves sick) and it bulged and got sick, this particular betta did not make it, but that was over a few months. I feed mine every other day at the least. I've also changed tanks with a betta before he also loved it and then he just seemed to get bored and didn't care anymore.

Do you have a heater? Bettas need warm water, about 78 degrees would be OK.

Bettas should be fed in small amounts twice a day, and let them "fast" one day a week. My bettas fast every Friday.

I find my bettas enjoy a 2-1/2 gallon tank with NO filter, but a heater, silk plants, substrate and some aquarium salt added for stress.