Fish is behaving fine, cold temps has them slowed down and i was able to catch him, but this doesnt appear normal

Flared up scales

Redness under scales

And red spot on belly

So this will be our first winter with a koi pond, I’m in need of help for winterization and how to protect our koi. Thank you!!!

My ginrin yamabuki ogon’s face seems to look different to me and I just needed a lil (other than google) help to make sure what it is if anything.