Fin Rot - treatment without salt/medication

[mpimezon]

Hello guys,
my fishee-boi has fin rot. he's in a 2.5 gallon tank with standard 76-78 F heater. no filter but I don't ever remember keeping the water dirty. in fact I do a 15% water change every 3-4 days. also hes been without water filter for the past one year since I brought him without any issues.
anyhow, I tried to treat it with aquarium salt (3 teaspoon for the tank - dissolved before adding) for the past two days, and I saw some swollen tummy in the morning today. I didn't want him to get a kidney failure, so I put him in fresh water, conditioner (regular lifestyle, for him). swelling has gone down.

so my question is, will it be okay if I do a 100% water change everyday without aq. salt to treat the finrot? I am usually apprehensive about aq salt, and now that I saw him with a swollen belly, I don't want to risk it.

what do you folks feel? I am ready to do w/e it takes. just need to do the right thing without putting him through a lot of stress.

[shadowpony]

copied from betta 101

1. Change the water 100% in the QT tank. This helps get rid of or discourage bacterial growth. Be sure to properly acclimate the fish when doing the 100% change in the QT.
2. Try and keep the water the QT tank is bobbing in at or around 76-78'F. This range discourages the spread of bacterial growth. When higher, it encourages growth, and when under 76'F, it is not safe for a betta.
3. Keep the lights off in the tank as well as the filter ( if you are treating in-tank), as the current will hinder fin regrowth.

if hes alone, you dont need a QT tank.