somethings not right

Question
I had my Beta for nine months, all that time he was swimming and happy to see it is feeding time. I only feed him 2 pellets once, the next day veggie flakes. the water is kept at 78 degrees. he chases the catfish once in a while, but as of Saturday 3/6 he wouldn't eat and mopped on the bottom of the tank and the same with Sunday 3/7, i noticed a bubble nest that is broken up from the filter. today i fed him and he ate like there's no tomorrow and sank to the bottom, tried to swim but leaned slightly sideways and sank again. now it is Monday evening 3/8 7:51 pm and the Beta is lying motionless on the bottom, i went to check and he is dead. I didn't see any parasites, bacteria or fungus on him.
i guess he was old? i got him back in September 2009 full grown, i mean he was larger than the other Betas, and a beautiful shade of red, so, i named him ares after the god of war since he was feisty.
I am feeling sad right now.

Answer
Hi Faye,
Your Betta was showing signs of Swim Bladder Disease.  This disease is caused by poor diet, and overfeeding.  A betta should have one frozen pea a week with the outer removed, and cut into tiny pieces.  He was constipated, and constipation often goes unnoticed.  It eventually causes Swim Bladder Disease, and if left untreated will lead to Dropsy.  Dropsy is very difficult to cure if not impossible.
There is little information from Pet Stores when you buy a betta.  A betta should be in a heated 5 gallon tank.  In his habitat the betta's water may be shallow, but he has lots of room to swim.  Bettas kept in unheated tanks, small containers, bowls, and vases do get sick, and their lives are cut short.  Under 80 degree water, the betta is cold.  He is a tropical fish.  Vendors do not care, they are there to make money, selling their gadgets saying that Bettas will live in a small container.  They do, but not for long.  A well kept Betta will live up to 7 years when treated the right way.  When heating a tank for a betta, we must do this slowly.  One degree every two days.  Raising the temperature too quickly will cause death.  I am giving you more information as I do not know the size of your tank etc.  A betta should have a varied diet.  Here is a list of food the betta should have:
Betta Pellets
Betta Flakes
Daphnia...Daphnia is very important because it helps their digestive system
Bloodworms
Mealworms
Glassworms
Brine Shrimp
Plankton Flakes
One pea a week, and on the day you feed him the pea, feed him nothing else.  This is so he can clean out his system, and avoid SBD.
Bettas should be fed 2-3 times a day in small amounts.  We must always remember that their tummy is the size of their eye when feeding them.  Two pellets, or two flakes is enough for one meal.
If this disease is caught in time, it is curable.  Unfortunately we do not know that our bettas are constipated, then we tend to overfeed them, and eventually they die.  Information on bettas is so important, but seems to be so difficult to find.  
I'm sorry you lost your little pet.  I know how sad we feel when we lose a betta.  We get so attached to them.  From what you told me, I am quite confident he had SBD.  
Lynda