I may not be the best of fish mommies, but they seem healthy and well-adjusted (for goldfish). I keep mine in a five gallon pail in the 40 Degree (F) sun room. Probably closer to 4 gallons in the container. Without much food, the water seems clear for quite a long time. When they seem to be surfacing, I move them into another five gallon pail (already temperature adjusted) and use the old water for my plants or just toss it in the garden beds. No pump, no pond dirt, no bio-filter, no TLC. According to DH, they are luck to be alive! It's a cold cruel world out there.
I do have a pet store that would take the bigger goldfish each fall as they sell for a higher price, but I rather learn to like my fish and enjoy watching them through the winter . . . as well as appreciating the super-powered water for my plants.
How many inches of fish? Of the 13 that over-wintered last year, 7 goldfish were three years old and the 6 minnows were volunteers brought into my pond by passing birds. The goldfish were each fat and about 2.5 inches long, while the minnows from that spring were long and lean, also just over 2 inches in length.
I still need to get mine in. We have had low temps, but nothing that would cause the pond to freeze hard, just a layer of ice crusting the top that is usually gone by noon or so. It isn't the cold water, but the thick ice that gets them. No way for O2 to get in and common pond gases to get out. Eventually the pond freezes solid and THAT is not a good thing fish-wise. I am hoping the Grands will enjoy that chore again this year.