Betta Fish ailment

Question
We have a betta fish in one of the hexagonal tanks with the filtration system going.  We treat the tap water to make sure the chlorine and such is minimal when we change his water.  We feed him twice a day the Betta Bio-Gold and keep his light on while we are home.  He is not near an air source to get too cold.  I have had many betta's in my day and have had no problems keeping them alive in the past.  This one seems to have developed this air bubble like mass on the top of his top fin.  It goes and comes as the pocket fills with air.  When not filled with air his fin just hangs next to him however when some air gets caught in it the fin floats above him.  It doesn't drag him topside or anything but it doesn't look the most comfortable.  I was wondering if you had heard of or seen anything like this and how to treat it?  We have been using the tank now for 7 or so months and the male betta is the only fish i the tank.
Thanks,
Nicole

Answer
Hi Nicole;

It may be beginnings of finrot. Or, if he has exceptionally long fins maybe the top one can't support itself anymore. It might be worth treating for finrot anyway. Here is a link to an article about it with treatment suggestions just in case;

http://www.healthybetta.com/articles/Illness%20Diagonsis/finrot.html

Another good site;
http://www.bettatalk.com/betta_diseases.htm

I hope he gets well again soon.....

At Your Service;
Chris Robbins

At Your Service;
Chris Robbins