URGENT - betta is dying

If this is due to a lack of oxygen in the water, when could I expect to see an improvement? He still looks really bad.
 
I would do a water change and raise the level a bit so the filter can run and maintain plenty of agitation.....that should help bring more O2 into the water.
 
I did that about an hour ago, and still no improvement. He's lying on his side on the bottom again, still gasping. If anything, he looks worse. Oh, this sucks
 
He still looks bad, but he was able to swim to the top just now and get some air. The filter is running, and the tank is just short of full to create some agitation in the water. Lights are off.

My husband and kids voted me down, so we're headed out of state to spend the holiday with family. I know I can't do anything else to help him, and no stores are open for me to even throw together a Thanksgiving dinner, but I feel like a murderer for leaving him. Maybe by a sheer miracle he'll pull through. Ugh, I feel horrible.

Thanks to everyone who helped this morning, especially Dirtydawg.
 
We're back, and amazingly, he's still alive - but just barely. He was hanging out on his favorite leaf when we got back, and swam over to greet us. I thought he'd made a remarkable recovery, but now he's back on the bottom of his tank on his side, still gasping.

I'm going to do a water change just as soon as my husband gets back with some new Prime, but don't know what else to do. Now I'm not so sure that it is a lack of oxygen in the tank, but I asked my husband to pick up an air stone as well. Do you think I should put it in - or can I give him too much oxygen (2.5 gallon tank)? The water level is low enough that the filter has a slight waterfall effect, so I should think the water already has enough oxygen in it, but gah - I'm flying blind here.

Also, I fed him 1 pellet when we got home when he came up for air, but maybe I should hold off on another? He last ate 2 pellets Thurs morning.
 
That sucks :(
I'm so sorry
 
Sorry about your betta. Hopefully once you set up the air stone he will improve. Good luck hope he gets better for you. You're doing all you can for him.
 
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