Is my fish dying?

Question
This is a starnge situation.

I came into work (where our fish, gary, resides) this morning and our fish looked completely normal down in the bottom side of the bowl. I peeked down at him as I passed by to say hi, and he had a total freak out, thrashing around in the corner.  I realized maybe he was terrified of my black scarf and rushed away to take it off.  When I returned, literally seconds later he was floating on his side at the top of the water and his gills were all swollen and expanded.  We thought he was dead.

But then.. he started to move.  But not normally.  He appears swollen around the gills and kind of along his back and he cannot seem to right himself up.  He is stuck on his one side. Now he just floats at the top of the water.. on his side.  I think he is broken and dying.  What happened?

Answer
Hi Gloria,
Your Betta seems to have Swim Bladder disease.  This disease is caused by stress, overfeeding,  poor diet, and poor water conditions.  It begins with constipation which often goes unnoticed, and if not cared for, will lead to Dropsy.  In the early stages of this disease, you notice that his tummy is swollen.  His tummy is just below his chin.  As the disease progresses, the betta swells up, and his scales are lifted.  
Feed him a cooked frozen pea with the outer layer removed.  Cut the pea in tiny pieces, and feed them to your betta one piece at a time, making sure he eats it, and that is does not fall to the bottom of the tank.  Change all of his water, and treat him with "Tetracycline"  Do not wait, as this disease if not treated quickly, will cause death.  Do not add aquarium salt, as this would not help him with this disease.  Wait until he is all better to add aquarium salt.
A betta should be in a 5 gallon heated tank.  He is a tropical fish, and need water temperature of 80-82 degrees.  Under this temperature the betta is cold, and will get sick.  In the betta's habitat, the water may be shallow, but they have lots of room to swim.  They should not be kept in bowls, vases, small tanks, and any other gadget sold for the betta.  Vendors do not tell people this, do not give good information, and do not care.  The customer who buys this little fish get very attached to them, and sometimes find out to late on how to care for their betta.  Some vendors are there to make a buck, and this is all that matters to them.  When a Betta is well cared for, he will live a long time, up to 7 years depending on the age he is when we buy them.
Bettas should have varied diets.  Here is a list of food the betta should have:
Betta Pellets
Betta Flakes
Plankton Flakes
Daphnia ( This food helps with their digestive system.)
Bloodworms ( This food should be given as a treat, and never their main diet)
Glassworms
Frozen Brine Shrimp
Wingless Fruit Flies  ( Some pet stores have them)  If not, you can do this yourself if you want to.  You will find all the information you need by putting "Wingless fruit flies" on Google.
Peas  ( one pea should be given once a week, and on the day you choose to give him the pea, feed him nothing else for the rest of the day, so he can clean out his system)
Feed him small meals, and never a big meal.  His tummy is the size of his eye, and we must always remember this when feeding them.  Two pellets, or two flakes for one meal.  He should be fed 2-3 times a day.
His water should be changed completely twice a week if he is in a bowl, and once a week if he is in a five gallon tank.  If his water is cycled, you must remove 25% of his water weekly.  Cycled water means, that he has a filter, and his water chemistry is "ZERO ammonia"  " ZERO nitrites" and the nitrates should be low.
When bringing up the temperature for the betta, this must be done slowly, very very slowly.  One degree every two days until you reach the right temperature.  His water should not fluctuate.  Fluctuating water is very bad for fish.  When fish are kept without a heater, their water drops at night, goes up during the day, and this can be deadly.  The only way to heat a tank properly is with a heater (Thermostat) and never with a light.
I hope this information will help, and that the little man will recover.
Lynda