Greg: That should be in the Koi That Fail thread!
Actually, I think it is an interesting fish in several respects. First, the lateral patterning showing up talks about doitsu heritage and some links to Shusui. Second, it is not uncommon for metallics to become duller as they age, but I do not recall so complete a loss of shine on an Ogon that size ever. I would not have thought it would happen. You have a truly unique mutt of a carp. If you find no buyer at that price, find someone who will take it for free to preserve it as a rare example ... of whatever. But, do it quickly. It is urgent you get it a new home. Koi like that have a way of becoming very friendly. Then sentimentality takes hold. One day you find that you are spending your weekends caring for crapped-out fish, postponing home improvements to add filtration because they've grown larger, and contemplating the expense of a new pond so you have room for a few decent koi. You can save yourself now. In another month, you may be in too deep to escape.