Water Gardening: Sick koi?, 1 by art_n_garden

art_n_garden wrote:
My yellow koi has developed these black spots all over her back. It's been at least 3-4 weeks, with no sign of improvement. She used to just have clear, clean looking yellow scales. Her behavior has not changed at all, still the leader of the pack, eating and swimming as normal.
I searched quite a bit, and the only thing I found was Koi Black Spot- http://www.inlandkoi.com/koidisease.html
But I am unsure if it is correct. It's supposed to be fading away within 6 weeks, but I see no change.

So I was not worried, but now as winter is racing up to us, I'm worried this will compromise her immune system. Any ideas as to what this could be? Or what I can do to help it?