Extreme fin rot- need help fast, almost at body.

[Norichan]

Housing
What size is your tank? 3g
What temperature is your tank? Unknown
Does your tank have a filter? Yes
Does your tank have an air stone or other type of aeration? Yes
Is your tank heated? No- my apartment is warm and the temperature remains constant
What tank mates does your betta fish live with? None

Food
What type of food do you feed your betta fish? Freeze-dried blood worms, bettamin flakes, omega one pellets
How often do you feed your betta fish? Every other day

Maintenance
How often do you perform a water change? Weekly
What percentage of the water do you change when you perform a water change? 50% weekly, 100% once a month
What type of additives do you add to the water when you perform a water change? AquaSafe water conditioner

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Ammonia: 'Ideal.' I never let it get past 'safe,' and I use jungle-brand test strips
Nitrite:
Nitrate:
pH:
Hardness:
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed? His tail is almost gone
How has your betta fish's behavior changed? He's listless
When did you start noticing the symptoms? A couple months back
Have you started treating your fish? If so, how? I began treatment immediately, using various medicated tablets. I followed the instructions carefully. When one didn't help, I tried another, and another- nothing's killing it. I was careful to select ones for the appropriate type of rot.
Does your fish have any history of being ill? Aside from this persistent rot, no.
How old is your fish (approximately)? Unknown, I bought him less than a year ago.

~*~

So, like I said above, I've been carefully and rigorously medicating Aloha, my yellow half-moon, but nothing's taking. I've also been making frequent water changes, and adding salt in acceptable amounts. He's been relocated to a critter keeper which gets a daily water change. NOTHING WORKS. I have tried three different medications on him and nothing is taking, and the rot is getting close to the base of his tail.

Is there some kind of super-powered rot killer I haven't heard of that people know about? It's bacterial, the jagged-edges kind.

I also heard someone suggest amputation (I would NEVER do such a thing just on a hunch, which is why I'm asking, because I don't know better one way or the other). Not the whole tail, obviously, just the edge... desperate and inadvisable, yes, but I'm really running out of options. Like I said, nothing is killing it, and I've been medicating/water changing/salting him persistently since he first started to show red on his tail.

Please, some expert, come and tell me what to do. I love my fish...

[SwimmR]

Have you posted a picture of it? Are you certain it isn't tail biting?

[Norichan]

I am 100% sure it isn't biting, it's discolored and icky at the ends.

[fishies93]

Which medications have you tried so far? Finding a medication/antibiotic that fights gram negative bacteria is really important. Aquarium salt can also be effective in repairing damaged fins.

[Sakura8]

Norichan, can you describe the rot? Are his fins edged in black? Do they seem to dissolve overnight? What medications have you tried?