Hi LBBJ,
I haven't been here much for a bit due to work and such, but I had shoulder surgery last week, so now I have some spare time while recuperating, and I found your pond thread in my search for things to read and look at.
I don't have much to say except wow, what scope and vision you displayed.
We inherited a small [1/8-acre] earth bottomed pond when we bought our log house which is in an appropriately wooded country lot of about 8 acres in 1994.
When we moved in, it was essentially sterile except for polliwogs/tadpoles, even though it was a couple of years old, so the first thing we were told to put in was flat head minnows,which we got a couple hundred of and then some weeks later, we added about a dozen koi and 10 channel catfish fingerlings [which we were told could not reproduce in the still water of a pond].
Long story short, our koi and minnows are thriving, but despite multiplying like hyperactive rabbits to the point where they were out-competing the koi, the channel catfish eventually all died off after a really long hard winter where there was apparently too much ice for them to cope with [although we do/did run air pumps w/ aerators year-round.