I do not know what the minimum size is for a good fishable pond - the other folks have offered some good advice.

There are several small ponds, and some stocked storm-water retention ponds within several minutes drive of my house. They are all good fishing, bass, crappie, catfish, bowfin, pickerel -and all caught on a fly.

My goal is to catch that darned big Koi I have seen swimming around in a local pond - a storm-water retention pond.