Swollen silver dollar

Hi, I’m reaching out in case anyone may be able to help.
I have some experience with tropical fish, I’ve had a 150 gallon tank running for 20 and have lost fish over the years. Right now I have a silver dollar around 15 years old that seems to be bloated. I feed him peas (skinless) and have used API, he eats and swims, his swimming is controlled (doesn’t bump into the glass) I’m in Canada where they recently banned fish meds from the shelf.



any input is appreciated

Wow. I've never seen anything like that before. Continue with the peas as that may help.

At 15 years old, maybe nature is just taking its course.

Sorry I couldn't help.