I agree with Henry...the situation is stress induced and the expectation is that in time this koi could very well recover to her former self.
over the decades one thing I've learned is that for shiro utsuri's or tancho
kohakus, they are the "canary in the coal mine" meaning anything goes awry in their water conditions and they are the first koi that red flags it for you.
My sense is that you stressed more than she did.....i think arnoild schwartzenagger said it best....." I'll be bock "....and so will your shiro......
