I don't think it would be worthwhile to build for that purpose unless it is at least 10,000 gallons and has a good area of at least 42-48" deep. Shallow ponds get too hot in summer, and in your area could freeze solid in winter.
My minnow raising pond is about 18,000 gallons, 3.5 feet deep, and is barely worthwhile as anything but a sediment pond. I have some Gambusia and small Koi in there now.
