Goldfish Question

[Dieses Madchen]

After 2 years, with proper conditions I imagine they'd be about 6", maybe more for commons. They're this size in a 10 gallon? I guess my link went unread, upgrade to a 40 gallon.

55 gallon tanks are the second most popular size sold in the US, and can be found used for 50 cents per gallon, this is the route I'd go for the 3 goldfish, which are actually pond fish.

I bought a 55g yesterday second hand for $30. They are pretty easy to find for a good price if you know where to look