What is one to do?????????????????????

I did battle such problem with a few males once and after trying every antibiotic and fungus medication I was just about to throw the towel and say my farewell to my poor little fish :(((((. But the rot had not anticipated one thing: It was dealing with FAITH. And Faith doesn't give up that easy. So it was a stubborn rot? It had knocked at the right door. It was going to have to deal with ME. And I was more stubborn than it was. Hah!

For drastic disease, drastic measures. I decided to perform rot surgery, as I call it, on all my affected males (about 12 of them). WARNING: Do not try this unless you are already experienced with bettas. This is how it works: First off you need Mercurochrome. (I think that's the right spelling?). Anywhooo, since I could not find it here (used to be that everyone used it to disinfect cuts and minor wounds, but now they have powders and ointments for that) I asked my parents to mail me 2 bottles from France. This is a red colored liquid (super messy). If you cannot locate some, similar results may be achieved with hydrogen peroxide (for wounds, not for hair!!!). 

The surgery will require quite a lot of betta manipulation and you have to be careful to not hurt the fish. I have no problem whatsoever but I have been handling fish for years and years now. 

To see a large version of the photos below, click on them.

You will need a paper plate, a couple of paper towels (or a piece o foam free of chemicals or detergents), a small soft brush (like for painting with water colors) and your mercurochrome or hydrogen peroxyde, and don't forget a fish net. 

Prepare clean water, same temp as your fish jar water. 

Net the fish. Gently place it on the paper plate. 

Wet the paper towels so that they are soft and moist (but not dripping wet). Fold them and place the towel on the fish, to hold it down gently. Do not apply pressure. The weight of water should suffice to hold him down, if not (some fish are cooperative, while others may flop about) place your fingers on both side of fish (tucking him in). Make sure to cover his head. If it cannot see, it is less likely to struggle. Note that on the photos above, I am using a soft piece of foam material (free of detergents or chemicals).

Make sure that the tail and end of tail and dorsal and anal fins are sticking out. Take your brush (still dry or ever so slightly moist)), use it to spread the fins onto the paper plate as in photo. Be gentle.

Then dip brush in medication, and apply medication to the affected rotting areas. BE VERY CAREFUL TO NOT GET THE MEDICATION ANYWHERE NEAR THE HEAD OF THE BETTA, ESPECIALLY HIS GILLS. As long as you hold him down gently, he should stay put an his head should be protected by the towel . Allow the medication to marinate for about 1 minute. The whole time, holding the fish to make sure he doesn't flop around and end up head first into the medication. One words of advice, do not put too much medication on brush so to not create a huge mess on your plate and have the liquid run too much. Put just enough to cover the rot area and area right above it. 

After 1 minute, take your fish net, remove towel and promptly use the net to wrap the betta up and catch him back into the net, Make sure net is moist (not dry). Once in the net, you can allow another minute to go by before rinsing him. 

Then take the clean water (same temp as betta's water) and very gently rinse the fish out, to take out excess medication. A few seconds should suffice. 

Now Mr. Betta is ready to return to a clean sanitized jar with fresh water. Gently dump him out of net into new water. He will clamp his fins and seem a bit pissed off for a while. Worry not about it. The next day he will look much better (back to normal). His fins may look red (if you are using my mercurochrome) or a bit "melted" if you use H.P. Once again this is normal. It might be necessary to repeat this surgery again in 1 week intervals for about 3 times. In between, do add fin rot antibiotics to the water as usual. 

No rot has ever survived this. All the bettas made a 100% recovery and their fins grew back to be normal and beautiful again. Older bettas will not grow back fins as fast or as much, but the main goal here is to stop the rot which ate the fins in the first place. Once again, this is a "surgery" and is not to be tried by novices or done unless everything else has failed (antibiotics, etc...). If you do decide to try it on your fish, you do so of your own accord and at your own risk.