wrote:

about the same relationship as between chimps, gorillas and humans.

http://www.itis.usda.gov/servlet/Sin...h_value=180090
we are both in the family Hominidae
Ingrid

Koi are "common carp", Cyprinus carpio
Goldfish are Carassius Auratus
Both belong to the family Cyprinidae

And Janet could have called me on the relationship of carp to goldfish -
you're right, it's not that close, but they _can_ interbreed. I've never
heard of a case of interbreeding between hominids, but it might just be
that they're all more picky. otoh, someone was promoting the theory
recently that H. Neanderthalensis never died out, it was just absorbed
through interbreeding with H. Sapiens (of course, they were the same Genus,
anyway).

I'll go so far as to take your analogy and say that Koi might bear the same
relationship to wild carp as Golden Retrievers to wolves (taxonomists might
still argue, but some do claim wolves and dogs are the same species).
Golden Retrievers are not ideally built to live wild, but occasionally they
do so anyway, and it only takes a generation of random breeding (and
selection) to breed right back to a perfectly capable wild animal. Those
of us who keep Koi in unheated ponds year-round, have almost certainly got
second-generation Koi that are indistinguishable from wild fish except that
they're still more colorful.
--
derek