Minimum koi pond size

[AquaAaron]

Hello all!

I wondered If i could get your opinions on the minimum size pond to keep a few Koi realistically, not to grow out as show koi I.e. 3ft size, but just to keep generic koi long term.

I currently have 3 babies (3" koi) in my 130 US Gallon above ground goldfish pond, and i would like to give them a permanent home as they get larger ofcourse.

any advice or recommendations would be appreciated, I can build the pond from wood to save money 

[gardenman]

I don't have any koi currently as my 300 gallon pond is a bit small for them. When I've had koi in the past they've gotten to 18"+ in about a year.  Once they reach that size they tend to slow down in growth, but they never really stop growing. The biggest koi I ever saw was about four feet long and weighed 90+ pounds. That's a big, big fish. Most don't get that big, but 24"-36" isn't uncommon. Filtration for fish the size of a small dog is kind of important. Serious koi keepers tend to go with rotary drum filters that remove solids from the water and then bakki showers or moving bed filters of some sort for biofiltration. 

Back to the original question, what's the minimum koi pond size? I'd say 1,000-1,500 gallons would be a good minimum. You might want to look at some of the Intex (or similar brands) of steel framed swimming pools. They're pretty cost effective ways to hold a lot of water at a low cost. They can also be taken down to be moved should the need arise. If you live someplace where winters get very cold you can even move one inside to a garage or basement for the winter. (Humidity will be an issue though.) The good news is you wouldn't have to heat it since koi can tolerate very cool temps.

[Patrick_G]

If you’re building with a wood frame then maybe an 8’x8’x3’ deep would be perfect. An easier, but smaller option would be a 8’x2’ deep round stock tank. 
 

I absolutely love koi but have decided that goldfish are almost as fun with a fraction of the upkeep and cost. 

[FriendlyLoach]

I would say 1000 gallons. I know that is not really realistic, but that would be best. I have a koi in my 600 gallon pond, but once it gets really big I plan to put it in a public koi pond.