Huge betta

[TheAvs21]

Thank you, I will up the percentage of my water changes, and I just ordered the omega one food you mentioned, I have the new life spectrum food mentioned already. I will try a combination of those and start feeding a normal amount again. And will start a new treatment of the Epsom salt as well.

[TheAvs21]

UPDATE(and another question)
Thank you very much, my last post was a Saturday, and I upped my water changes to 90% and started feeding a normal good amount of food. Everyday after that Vader had some HUGE good all brown looking poops and he himself looks way better and not nearly as bloated. Then on Wednesday I got the omega veggie pellets in from order and put those into the rotation of food. Then Thursday and Friday (today) he had 2 separate HUGE poops for me to vacuum out with his water change. And he looks amazingly better, almost back to normal size. He is still not back to completely normal size but very close, so I was thinking I do another treatment of Epsom salt tomorrow again and if all goes well he will be looking a normal size and ready to put back in his home next weekend.

My question is I have a bunch of white stringy ish type of stuff floating all around the tank, even when I do 90% water changes I try to vacuum out as much of it as possible and when tank is filled back up it looks like I didn't even put a dent in the amount of white stuff floating around. It is attached to the glass, the heater, the thermometer probe, the Betta hammock, the Betta Vader himself even, it is attaching to his long flowing fins. I have never experienced a white stringy floating substance before in a tank. I have also noticed this stringy substance started to get bad around Monday and at the same time I noticed Vader hanging around at bottom of tank next to heater even though tank is 80.5 degrees Fahrenheit at the same time this substance got real bad. He doesn't hang around by the heater all the time, but he never did that at all until the substance got real bad around Monday.
I have attached some pictures to show what I am talking about. Kind of getting worried and wondering if I should put him back in his home to get away from whatever it is since it seemed to affect his behavior some.

Only thing in tank other than mentioned is the sponge filter and the Indian almond leaf. Filter has been in the whole 2 weeks tank has been set up and never used before this set up. Indian almond leaf was added middle of last week, almost whole time this hospital tank has been set up.
It may be hard to see the white substance in the pictures, my camera on phone is not the best, but it is literally everywhere.

I very much so appreciate all the help, advice, and information given.

EDIT: also I forgot to mention what has really been worrying me, is when he is hanging around down by the heater I can see his gills moving very rapidly like he is breathing heavy. He only does that when down by the heater. When he is up in his hammock i don't see his gills moving rapidly or anything unusual.

[Autumnsky]

Well a possible bit of relief is that the warmer the water, the harder the fish has to work to get O2 out, so seems to me because of the way the gills process the water they have to breathe more for the same O2 benefit.

Do you have anything circulating tje water?

You can clean the sponge filter gently, with declorinated water as a start.

I think circulating more water may help. I'm not sure what it is specifically. It's too hard to see the pics detail.

Check what freshwater sponges look like. See if they might look the same.

Do the stringy things wiggle like worms in the water, check Planaria, and Planaria swimming.

Maybe someone else can tell.

Happy to hear your fish is doing much better!!!

I had one Betta fish which required the ES for the rest of it's life at 1 teaspoon per gallon. But he lived in his own 5G container and probably lived another year.

[TheAvs21]

Googled freshwater sponges and it definitely doesn't seem like that. They didn't wiggle or move at all, almost looked like decaying matter of some sort floating around. The only thing I had circulating water was that sponge filter. I did end up a couple hours ago just putting him back in his home and rinsing and wiping out the hospital tank and sponge filter. So far he has normal behavior in home tank but will keep a good eye on him now.
Thank you again for the help!