I am afraid my betta is dying...

Question
I have a male betta we've had for over nine months who has been completely healthy up until now. He lives in a large glass vase which I fill with well water and then add a few drops of Start Right to for good measure.
I left him at a friend's house while we were gone for two weeks and his water didn't get changed for the whole time. Usually, his water will be fine for that length of time but I think the little girls helped and put too much food in the water so by the time I got back it was badly in need of changing. The water was murky and very stinky, kind of like a sewage smell.
Yesterday I cleaned out his bowl and gave him fresh water. I noticed his color was not good at all. It's as if he's been drained of color all over his body but his tailfin still had some good color in it. I did everything the same way I normally do, and he seemed fine at the time. Last night I noticed him swimming funny. He keeps floating at the top of the water and when he stops he starts turning sideways as if he is going to go belly up. He corrects himself, swims around a few seconds, then stops and does it all over again. He seems to have trouble controlling himself, and it seems like he can't swim down very well, as if he were floating TOO much.
I've never seen any of my betta fish do this before. Any advice? Or is it only a matter of time before he dies?
Thank you.

Answer
Hi Amber,

The behaviour you have described is typical of fish with swimbladder disorder. The swimbladder is a gland near the fishes' stomach which, when the fish in injured or overfed, can become inflamed and cause swimming difficulty. It sounds like the little girls have indeed overfed him. Thankfully it is not often fatal.

It is brought on when a fish is overfed or sustains a knock, and the stomach swells, crushing the swimbladder. Treatment is simple though often slow: stop feeding until symptoms stop. Do not worry about starvation; bettas in the wild often go without food for up to a week.

Also, since you say he is having difficulties swimming, lower the water in his bowl a fair bit so he can get to the surface to breathe more easily (bettas breathe atmospheric air from the surface of the water).

I hope he recovers soon!

Prue