I need help with finding the right aquarium tank size for my already over crowded fish-tank.?

For 2 fancy goldfish, 30 gallons is recommended. I would choose between 35 and 40 gallons for the goldfish and minnows, and there might even be some room for the minnows to breed if they want to. For one fancy and 5 minnows, I would say 25 to 30 gallons, but for 2 fancies, you will need some space.