stress coat +water conditioner + aquarium salt sound good. But salt i would really increase up to 3 tsp/gall. You can increase it with your next water change. Use it minimum for 10 up to 13 days. Do daily water changes. Do not stop salt even if you think his tail is better. On another hand if in 4-5 days you think salt doesn't help or at any time if you think he is worse ,especially changes in his behavior(lethargic) or stop eating you need to treat him with medication.
I would get API Triple sulfa . Just make sure you don't have allergy to sulfa. Another choice for fin rot Jungle Fungus Clear that contains two antibiotics that treat gram negative bacteria (most fish illnesses including fin rot, are due to gram negative bacteria), or API Furan 2, Bifuran, Maracyn Plus. With Maracyn drugs you need to be sure that your ph not higher than 7.0 because maracyn's drug would not work in high ph.