Need help with my Betta.

AND YOU BETTA HELP. Har har. Anyway.

I have determined he has some kind of digestive issue, because he keeps coming to the surface, and trying to jump-gulp at the surface, then heading down to the bottom again. Not out of the woods yet. I'm using aquarium salt in his 0.5 gallon hospital tank (1/2 teaspoon), and he seems to be doing betta (heh) than he was. He's still pretty colorful. I've attached a picture. Not as clear as I would like because of the air bubbles on the side of the tank.

How long have you had your betta? Is this a new behaviour for him? They do breathe from the surface, is the rest of his behaviour normal? Does he seem bloated? Also I'm sure someone will ask for your water parameters if you can post them as well.

Not sure about water parameters, but I just cleaned his tank to prepare him to move back in it. He seems to be doing better today, Had him for about a month or two.

What you described looks like ammonia poisoning.

Even more if the fish was relieved when you moved to another tank with clean water and a little salt.