swill, I can't believe it's still alive
It's possible it has an intestinal blockage which is causing food in it's gut to press against it's swim bladder, amongst other organs.
If that's the case, I'd suggest you keep feedings down and try to feed it something that will help with digestion.
If it ever starts to recover, again feed it something to flush it's system.
For us it would be fibre ....
Good luck !