Sorry that your fish is sick I'll see if i can find any information for you, i'm by no means a Betta expert (more of a loachy / catfishy / pleco-y kinda girl).

Couple questions --
1. What size of tank is he in?

2. Have you checked the water parameters for Ammonia, Nitrates and Nitrites (and if so could you post the results)?

3. From what i've read, you've been treating with
- Melafix (based on tea-tree oil, antibacterial that generally helps with fin and skin repair)
- TcII (general antibiotic - for common diseases such as bacterial tail rot, cotton mouth fungus and gill disease)
- Maracyn-Two (broad spectrum dual antibiotic - effective against a variety of bacterial diseases like Mouth Fungus, Popeye, Dropsy, and Ulcers).

Have you ever tried Pimafix (low grade anti-fungal) or any stronger medications?


4. His current symptoms appear to be fraying fins, scale loss, and possibly a fungus. Does he look like any/several of the fish or descriptions here?
http://www.bettatalk.com/betta_diseases.htm


Do you have a clearer picture of the fish, and what he looks like? I have to go to BigAls anyway to get more foods for the voracious crew, and hopefully someone there could be more helpful with a diagnosis (i can print this out and take it with your replies if thats cool).