Advanced Fin Rot

Question
QUESTION: Dear Jaymie,
I'm tired of my betta's rotting fins. I dont know whether you remember me. You've helped for the same case a couple of months back. I'd sent you a photo of my sick betta, which had some pathetic fins then.
As per your advice, I administered aquarium salt (2 tb spoon per gallon+100% daily water change).Its almost 2 weeks that I've been doing it. A slight (almost negligible) improvement was noticed 2 days back. But now things have got all the more worse. I don't think aquarium salt is working wonders on him.. What shall I do? I'm thinking of giving him a larger 4 gallon home.
As far as the treatment is concerned, could you give me a more reliable alternative? I very well know that medicines are the last resort, and that you may not prefer using them. Anyways, I've bought some Oxytetracycline and Melafix for him.. I haven't administered them however, as I need your expert advice on it. Please tell me whether oxytetracycline works the same as tetracycline. And how much should it be dosed for my betta..
On the whole, dear jaymie kindly let me know of a promising treatment for my betta's rotting fins..
Thanks a lot,
Mathews Joseph

ANSWER: Do not use the Melafix, it is not good for him. Do you have a heater in his tank? If there is no heater, my suggestion is to get one. No medication will work if his water is too cold. Make sure it is set to no less than 80 degrees at all times. I have never used the Oxytetracycline but I am sure it will help. Make sure you follow the directions and remove the carbon in his filter if he has one.

---------- FOLLOW-UP ----------

QUESTION: Thanks a lot dear Jaymie.
Actually I'm from Kerala (the southern most state in India). And here the temperature always ticks between 78-82 degrees.. As such, I havent installed a heater in his tank. What I've got is 500 mg oytetracycline tablets for animal use.. I'd like to know how tablets are normally administered to bettas. Are they mixed with the food, or powdered and dissolved in their water?
Expecting a quick reply..
Lots of thanks
Mathews Joseph

Answer
Unfortunately, I do not know how to administer medication in tablet form. Here in the US, we have the medication in liquid form. Even though the temperature there is warm, it is not at a steady temp. It goes up and down and that is what causes a fish to stress. I am thinking that is the main problem right now.