Help ID sick koi

[Ynott116]

Was rapping up the pond for winter and noticed this fishes head was looking a little off, took him out and discovered this any idea what it could be? I was thinking of treating him with Seachem KanaPlex.

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[Mmathis]

Are you referring to the grayish spots? Could it be the natural color (in no way am I an expert on fish disease), and you just didn’t notice it before? How is the koi acting otherwise?

 

[Ynott116]

Are you referring to the grayish spots? Could it be the natural color (in no way am I an expert on fish disease), and you just didn’t notice it before? How is the koi acting otherwise?

The koi is acting fine, still eating even immediately after moving him to a quarantine tank. Initially that's what I thought it was as well was a growing spurt or maybe he lost the scale somehow but mind you that was two months ago and it was much smaller. Pretty much overnight it got much bigger!

 

[WaterGardener]

Koi pox? That would be my guess, but definitely no expert either.

It's a fairly common virus that gets worse in colder temperatures. It will often go away once the water warms up, but can reoccur when it gets cold again. Some fish eventually become immune and stop developing it.

Since it's a virus there is normally no treatment, but the fish don't seem to suffer any ill effects from it.

If that is what it is, there is no need to quarantine. The pond is already infected with the virus.