Betta suddenly bloated and floating vertically :(

[LindseyR]

I went on vacation for 4 days and left explicit directions for the neighbor (who was also caring for the cat) on how to care for my Betta, Oscar. The cat is fine, but Oscar is looking quite sick, and I believe he wasn't fed or heated correctly.
I travel to and from my school for holidays (a few times a year) by car and Oscar usually does very very well in the car, and has no issues recovering after. Last night, I put him back in his tank and he seemed to be looking a little listless and just sitting either on the bottom or on his leaf hammock near the surface, and didn't eat the 3 pellets he usually gets. This morning his belly was totally distended and pale, and he was floating completely vertical and gasping at the surface for air.
I warmed his tank up a degree and lowered the water level, but I'm at a loss for what to do now. He's 2 years old, and these symptoms are sudden. I'm thinking either swim bladder disease or bloat. Any ideas?
Thanks!

[mjoy79]

I'm sorry to hear about Oscar :( I hope he can get back to normal soon. If you could answer as many of these as you can, that might help in figuring out what is wrong with him. Also if you have a pic of him that would be helpful too!

Housing
What size is your tank?
What temperature is your tank?
Does your tank have a filter?
Does your tank have an air stone or other type of aeration?
Is your tank heated?
What tank mates does your betta fish live with?

Food
What type of food do you feed your betta fish?
How often do you feed your betta fish?

Maintenance
How often do you perform a water change?
What percentage of the water do you change when you perform a water change?
What type of additives do you add to the water when you perform a water change?

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Ammonia:
Nitrite:
Nitrate:
pH:
Hardness:
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed?
How has your betta fish's behavior changed?
When did you start noticing the symptoms?
Have you started treating your fish? If so, how?
Does your fish have any history of being ill?
How old is your fish (approximately)?

[LindseyR]

Thank you for your response, but Oscar has passed :(