can our Betta be saved?

Question
We bought a male Betta for my 5 year old son about three months ago.  He is alone in a 1.5 gallon tank.  We had been changing his tank about once perweek but fell slightly behind around the holidays.  We use tap water with dechlorinator drops.  He seemed very happy, making foam, swimming around, eating, hiding in his little house or fake plant.  However, the past few days he did not really respond to his food.  I noticed a grayish film around his mouth.  Today I thought he was dead when I found him floating around with his head up and his tail down, completely vertical.  He will respond by swimming up to the top briefly, then floating back down.  I have him next to our cast iron radiators to warm his tank.  Also I added Bettafix rememdy today.  Please let me know if there is anything else I can do.  Thanks so much.

Answer
Hi Jen;

Poor little guy. It sounds like columnaris. Here is an article about it and how to treat it;
http://freshaquarium.about.com/cs/disease/p/columnaris.htm

You have to scroll down past some of the advertisements to see the whole text of the article. I hope you can save him, but he is indeed very sick. One thing important is to not warm him up too much or the disease progresses much faster.

At Your Service;
Chris Robbins