Ponds are small ecosystems that have to be maintain by an outside influence.
what would happen if an artifical pond gets abandoned? will the koi evolve?


Actually if the pond is big enough to sustain the population as a breeding
population they will evolve and quite quickly. I just a few generations you
will no longer have the fancy brightly colored koi just carp evolved to survive
in the environment they are stuck in. Give it up, you are out of your league.

Moon