My Koi in quarantine update

I thought I would post a few recent photos of my koi with popeyes to show you how it's doing. This koi has displayed these symptoms now for over three months and while not getting better it also doesn't appear to be any worse. I guess this is what is known as a chronic illness, dragging on for months. Earlier I didn't rate it's chances but now apart from the eyes you couldn't tell anything was wrong. There are no problems with any of my other koi so it must have been a one off triggered by the fluctuating temperatures in spring.

I shouldn't really get too upset but she is one of my first koi and has been trouble free for over fifteen years and one of the family. Not particularly great in quality from Israeli stock if I can recall, she could best be described either as a poor sanke or a kohaku with a spot of sumi on her head, hence the family name 'Spotty'. Her redeeming qualities are that of a great shape and always friendly, or is that always hungry?

What's worrying is that this won't clear up before winter when the immune system shuts down, so I've decided to install a heater. I have talked about using antibiotics before but some people have suggested that these could make things worse if the type of infection is not correctly identified. It's not easy with koi health as you can't just call your local vet out to take a look. What I don't understand is if the kidneys have been damaged by the infection why only the eyes seem to be effected? Anyway hopefully in her sterile quarantine tank she can make a full recovery but I wish I could risk adding a friend for her.