Hi,
just joined today the forum but i have been following discussions here for some time now.

I noticed some kind of injury near the mouth of one of two leuciscus idus i have on my pond. They live there togheter with 3 kois and some goldfish.

I've just put him in a quarantine tank with an emergency water pump turned on. I would appreciate if you can give me some advise or ID the injury.

Here are some photos, i can take some other if needed.
https://ibb.co/h1K5ZJJ
https://ibb.co/HxvgK5y
https://ibb.co/M2Lt2Pg
https://ibb.co/WxVWcpr
https://ibb.co/27nknym

Thanks,
Nicoḷ