Swim bladder issue, not constipated

I agree that you should not use meds unless it is necessary.

I also think that age could be a possibility. 2 years is a very good age for a betta from a large chain store. I think the longest I had a betta that come from a chain store was maybe 3 years and some change. They usually do not live as long as betta that came from a breeder (stupid cups with dirty and cold water).

It is very possible that due to his age recovering from a wound would drain him.

When you say he lays at the bottom and can't get to the surface, does it seem like "sinks like a stone"? SBD is not only caused by overfeed (although this is usually the cause), it also comes from a simple infection. If he is sinking like a stone when I would add some Epsom Salt 1/2 teaspoon to 1 teaspoon per gallon of water. The reason why Epsom Salt helps with bloating/constipation is because it draws excess fluids and toxins from the fish. Epsom Salt is actually fairly mild on fish. I have a female betta with Chronic SBD so she always has a very low dosage of Epsom Salt in her tank and i've experienced no problems with using it.

My other guess that he got some sort of infection from his wound, even though it is now healed.

Epsom Salt is actually much less harsh then AQ Salt. you can use it for prolonged periods of time where you can only use AQ for 10 days max. He will be fine if you add 3/4 of a teaspoon per gallon, you can even do 1 teaspoon if you wanted.

It will take a few days for it take effect. If after a week you see no improvement then it is time to move on to meds. I recommend API General Cure. It is very mild on the betta's system and i've had good luck with it treating SBD due to infection. You can find this online and at Petsmart (Canada has Petsmart I believe).

The dosage I keep is about 1/4 teaspoon per gallon, sometimes a bit less. Epsom Salt will not harm your plants. It will however harm the snail. However, having a betta that needs a low dosage of Epsom Salt in their water is EXTREMELY rare. I've had bettas for 15 years and this betta is the first betta that i've had to do it with. So the odds are you will not need it in your tank.

I would treat him in his 2 gallons QT tank with the Epsom Salt. You do not want to do baths with the Epsom salt but rather add it into his water in the QT and have it be in there all the time. Since Epsom Salt can take some time to show effect, baths do not give the fish a chance to be exposed to the benefits. To add it, remove a cup or so of water from the tank, dissolve the salt in that and then over the course of 45mins to an hour, slowly add the salted water back into the tank. Epsom salt is very mild on the fish so it will not hurt him. Epsom Salt does not evaporate out but you will need to add some to new water during water changes to keep the dosage constant. So for example if add 1 teaspoon per gallon of water, when you change 1 gallon you will add 1 teaspoon to the new water.