Benign Vanilla wrote:

A week or so ago, I noticed a pretty big goldie swimming around in the VF.
It was in the upper pond which tells me, it took a ride through the pump,

That or it did the salmon thing, swimming up the waterfall.

When we brought him in he was distinctly black colored,
as he swam around in my SO's salad spinner.

eewww! I've gone right off salad.

After letting the water warm a
bit, I dumped him into the aquarium. I noticed however over a few hours he
changed from distinctly black to a golden color.

I don't know if he is a goldie, koi or koidlie as he seems to have
features of all three. Either way, do goldies, koi or donkey koi/goldies
change color over hours?

I can't say for sure about goldfish, but I've watched markings on many fish,
including koi, appear out of nowhere. Black pigments seem to be
particularly easy to turn on or off - though I'd normally expect the more
pigmented form to be the less stressed (sick fish often look very washed
out) but that seems to be the opposite of your case.
--
derek