This morning, I found my beautiful new blue ghost fish (he has actual baby blue on his face) very dead and puffy and floaty in the pond.
Yesterday afternoon, when all the others were swimming around like crazy hoping for food, I had a hard time spotting him. I think he was hiding, and possibly begining the decline that many fish get when they are introduced to a new pond and are not acclimated to that particular biological environment. I've had him a little more than two weeks, and thought he had been in the pond long enough, and that he was so big and hearty at the begining (the biggest and most expensive fish I've ever bought, about 1' or so), that he would overcome that issue.
But I can't think of any other reason for him to have died. Something had taken a few bites out of him, but this had to have been post-mortum, as no live, strong koi of 1' would have let himself be chomped on. Probably one of the baby turtles I have in there, until they're large enough to not be eaten by the adult turtles - would not have attacked and killed the fish.
I don't think he was attacked from above, as if by a bird or raccoon. No marks to indicate that.
Any other ideas for why he would have died?