For What It's Worth:
I saw what I think was an adult for $699 at a LFS earlier this year. I can't tell you if this price was reasonable. The LFS owner usually doesn't sell fish in this price range. And on other fish, sometimes he's way below other market prices and sometimes way above on certain fish. For some reason I remember that this fish was caught off southern Japan, but may be mistaken on that. It was a nice looking fish.