I just read the whole thread, and noted that someone mentioned the lack of common goldfish
Here are the four common goldfish that I am wintering. The small one is 3years, and was kept in a 29 gallon tank until last year, when I learned about their need for space. The others are his pond-mates. They live at my dad's house, and I offered to winter them because of renovation at his house this year. The tank is a 38gallon bow front

Keeping this clean requires two 50g filters, and twice weekly water changes, but they go home soon