Hi Everyone,

Every so often I see people post asking for the rule of thumb to
stocking fish. Usually the response is 1,000 for the first koi and 100
gallons for each additional koi. One has to wonder why the first koi is
hogging up 1,000 gallons while each additional koi needs only 100 to be
happy. Most people assume that this has to do with nutrient loading of the
water which is and isn't true.

In the aquarium world the rule of thumb is 1 inch of fish per gallon. It's
possible with the use of a fluidizer and big filter to get 12 inches per
fish per gallon. This 12 inches of fish per gallon is also achieved in some
fish hatcheries. It'd be possible to get a 12 koi to live in 1 gallon of
water.

I raise alligator gars. One thing I can say is that there sure isn't much
fish but they sure are long. One of my gars could live in a 5 gallon tank...
but he wouldn't be able to turn around. Instead he lives in a 75 gallon
tank.

When you hear "1,000 gallons for the first koi and 100 gallons for each
additional koi", what you should really hear is, "You need 1,000 gallons for
all of your koi to be able to turn and move around and swim. You need 100
gallons of water for each koi to deplete their nutrient load and limit the
size of your filter to something manageable".

Sam