Calculate the total volume of koi pond
Here's a formula:
Length (inches) x Depth (inches) x Width (inches) = Product
Divide that product by 231 to give volume.
Or for a cylinder: (Pi) x Radius2 (inches) x Depth (inches) gives a product.
Divide that product by 231 to give volume in gallons.
(Where pi = 3.1416)
How many koi can I put in my pond hold?
Calculate the "inches of fish" for the size of your koi pond
Inventory each koi, or derive an estimate, and add up the total inches of fish.
GOLDEN RULE FOR STOCKING KOI AND POND FISH:
"One inch of fish per ten gallons of pond water will do well if adequately filtrated and small, regular pond water changes are done."
What This Means:
Well, this is true for koi quarantine and hospital tanks. This is true for retail tanks. This is true, no matter if you believe it or not. Just like the laws of gravity.
"When your koi are sick, nothing you do will work until you remedy a crowding scenario. You can reduce the stocking density to the above, or Mother Nature will do it for you."
Then, your treatments will start to work.