wrote:

You can safely have 1" of Koi for every square foot of surface area.

We have a nice pond size calculator for figuring this out.

http://www.pondkoi.com/pond_calculator.htm

I can't believe they're still advertising that extremely antequated
calculation! You can _not_ safely have 1" of koi for every square foot.

That was a very rough rule of thumb invented for the aquarium hobby, back
when we all thought it was pretty rad to have a 30g aquarium. It works for
_small_ fish. The bio-load of a fish increase approximately eight-fold
every time you double it's length. The rule of thumb often cited here for
koi, is one koi in 1000 gallons, 100 gallons for each successive one. Not
a bad rule, as long as you don't cut it too close. 2 koi in 1000 gallons
can be tight.
--
derek