Why do you think the comets are interbreeding with the Koi? Could it not be
that the comets are merely breeding amongst themselves?

As far as getting the fry out, with a pond that large I would suggest using
a minnow trap. The kind you buy at a fishing or sporting goods store that
ususally looks like a tunnel with two funnels, one at each end. They allow
the fry to enter but not leave (sort of like "Hotel California").

Once you have them out of the pond there are several things you could try.
Is there a local pond or aquarium club where your could sell or trade them?
How about to a local fish or pet store? Other hobbyists or ponders?

If there is no other option there are several ways to humanely euthanize
fish but I will leave it to others to describe the methods.
"old dirtbeard" wrote in message
et...
Hello all,

We have a 2,500 gallon pond, two 3,000 gal/hr pumps (usually only run one
at a time) with a stream and waterfalls here in Southern California. We
had three koi at one point but lost two (one to a dog raid on our pond and
another to physical problems). We have corrected both problems.

We now have a single koi and several comets, but they appear to be
inter-breeding.We now have a great many (a couple dozen fry and larger
offspring), some black, some mixed colors, etc.). My understanding is that
these mules are sterile, but it seems like everyday I see more fry.

Although I am glad the pond is healthy and producing, I am concerned about
what to do about the potential overpopulation of the pond.

Do you cull a pond? (I hate to think about this).

If so, how is it done humanely?

Thank you in advance. We rescue spiders in the house and release them
outdoors, so the idea of killing our pond inhabitants is not attractive.

best,

OD