Koi with swim bladder

[Dyood]

hello, my dad pointed out to me that his koi is swimming upside down, when it stops swimming it just floats upto the top, so I diagnosed it as swim bladder.

I have fed him some peas and added in some pond bacteria medication, but is there anything else I can do for it?

All help is appreciated as I'm new to swim bladder issues and definitely ill and sick koi/pond fish