Patchy spot on cheek area of Koi?

[guthix]

Hello!

I've noticed this patchy pinkish? area near the right cheek/gill on one of my young pond koi (3-4 inches long currently) that I got a little over 2 months ago. At first I thought it had always been there, but I went back and looked at pictures I took and that patchy area is a newer thing - started noticing it a few weeks ago, I believe. Here are pictures for comparison:

When I first got it - https://imgur.com/gNhkYjq
Picture from a few weeks ago from GoPro - https://imgur.com/AhUeMsr

Any idea what this could be? Parasite or scratched against an object maybe? It is swimming, eating, and otherwise acting normal - same goes for all the other fish in the pond.

Water parameters:

pH: 8.0-8.2
Ammonia: 0
Nitrites: 0
Nitrates: 20 ppm
GH: 161.1 ppm
KH: 89.5 ppm
Water temp: 72-74 F

Pond size: ~200 gallons

Water maintenance: 20-25% water changes once or twice a week

Pond stock:
3 koi (3-4 inches long)
4 goldfish (two 3-4 inches long, one 5 inches long, and one 7 inches long)

Location: Southern California, Los Angeles area
Hobbyist level: Casual/beginner


Will be upgrading to a much larger pond next year. Thanks in advance for the help!!

[fly4koi]

Picture is not clear, need better lighting or just record a video instead.

Usually skin condition you can treat once with iodine (don't get into gill, eyes, mouth, etc.) and return to tank and see if it helps, but honestly can't tell clearly from the photos.

[richtoybox]

What I think I see appears to be a scrape, probably against some of the rocks. I am not sure that it is ready for any treatments, but keep an eye on it and if it becomes more red, then treating with iodine should probably be all that is needed.