Urgent Help With Betta with Columnaris

Question
I hope someone can help me. I have always had a healthy betta (my last one lasted 6 years, so I take good care of them). A few days ago, I noticed he wasn't greeting me or eating and he had a white, cottony spot on his side. After doing research, I realized he had gotten a fungal disease. I researched online the best course of action to take and I did a complete water change, started a 5 day Maracyn medication program, added aquarium salt, kept the kept the temp to 73, and took out the charcoal filter but let it run to aerate the tank. Yesterday was day 4 of the medicine and he looked a bit better, like it was clearing up and he was on a plant near the top of the tank - not eating but getting air. Today is day 5 and he looks worse. It's now almost all the way around him like a belt and he's staying on the bottom. He's in a 2.5 gallon tank with a plant and mossimo ball. My question is - if the Maracyn is not helping, what do I do now? I haven't been changing the water since the first day because the instructions on the box said not to. I don't have the water info (ran out of testing materials) but it's probably messed up because of all the Maracyn in the water anyhow. Should I change his water or will that stress him out more? Should I get different meds? Should I get him out of that tank completely until it's scoured? Can the plant/moss ball carry the fungus - should I toss them out? Someone please help! I keep hoping he'll get better and he's not - very sad.

Answer
Diane,
The first thing I would do is get him into a 5 gallon tank. He is in the minimum size tank for a Betta, but he will do much better in a larger home. His water temperature is way too low. He needs it to be between 80 and 82 degrees at all times. Having that low will stress him out, and will cause illness. There is a great medication for fungal problems called Jungle. I have heard it works very well. Since he is in such a small tank, a filter is not only unneeded, but also unwanted. Filter currents can also stress them out leading to illness. How much salt are you putting in his water? Have you tried instead a salt water bath? I would do a complete water change and try the other product. I am thinking that if you turn his heater up slowly to 80 degrees you will start seeing a huge change in him.