How fast do Koi grow?

It depends on conditions.

Genetics, food, water quality all play a role. Getting Koi to grow big is part of the challenge of the hobby...

So you want to start keeping Koi? Welcome to the madness.  We put this page together quickly because we found the results interesting and that they validate our choice to import Hikari Koi food. So whilst this page is advertorial in nature we hope that it illustrates the point about the role of food and the sorts of things you can do to get your Koi to grow big and strong and win all the shows... 

Recently a customer of ours engaged his son in a school experiment for growing Koi. The aim was to see the difference that food, water, temperature and genetics play in influencing the growth rates of a Koi. As a matter of interest we had no actual hands on intervention in the project whatsoever - we just got the results one day handed to us - our customer had mentioned the project in passing and so all we knew was that it was happening and which foods we had recommended.  

Baby Chagoi from a single spawning that the customer had recently spawned himself were used. Two porta ponds were rigged up with identical filtration, flow rates and location. One (pond 1) was heated and maintained at a constant 22C whilst the other (pond 2) was left alone and fluctuated between 12 and 20C.

14 fish were selected for each pond. Each pond was given 7 fish that were deemed to be much larger than their siblings and 7 average sized fish.

Pond 1 was fed 30g of Saki Hikari Growth 5 times a day. Pond 2 was fed 50g of Hikari Economy once a day.
And of course we expected the results to be very different. But even so we were gob-smacked.  Utterly Gob Smacked. With a capital G S...

Pond 1 gained a total fish mass of 7200 grams, whilst Pond 2 managed a total mass increase of 1825 grams. The single biggest fish increase was in Pond 1 - an astonishing 1220 grams.