I'm treating him for infection. The vase is a gallon, I am very busy to do 3 water changes a week. I never had this problem with one of my older bettas which lived in a gallon vase for 5 years. Test kits are not cheap where I live and well I don't know how to use them.
I think that the above quote may be part of the reason. You stated several times that you kept a betta in a 1 gallon vase for five years. I'm glad it's just a temporary measure and you realize now that vases are not proper betta homes.
I learned years ago not to buy a fish that I knew would eventually outgrow my tank, with the intent to buy a bigger one at that time. Life gets in the way and sometimes we don't follow through for various reasons and the fish suffers. I also wouldn't buy a fish and bring it home unless I had it's proper home waiting for it. Just some helpful advice so perhaps you won't get in this situation again.
Best of luck to you.