This info about Koi is from Schäperclause, W. Fish Diseases, Vol.1, 1991. A.A. Balkema, Rotterdam. p.195 & 198.
Recently the question was asked about how much does a Koi weigh that is a certain length? Here are some thoughts, and a few charts...
This study looks at the effect of feeding Azomite (hydrated sodium calcium aluminosilicate, a natural trace mineral product) to Koi. They found that it improved both growth and the immune response.
I found this study while researching for an article on nutrition. This work was done in 2015, and specifies the number of times to feed per day, the amount and the protein levels for various stages of development in carp (they also cover catfish and prawns). In many parts of the world, carp is an extremely important protein source and they are thus raised commercially. As hobbyists, we can certainly learn a lot from these types of studies where the researchers want to understand how to maximize growth in an environment where there is little natural food in the pond.
This is an excellent study that evaluated changing out fish meal for plant proteins on carp (Cyprinus carpio) of various ages. The researchers evaluated growth rates using various proteins and various amounts of protein. Reading this will help you understand how to better evaluate the labels on Koi food bags.
Medicated food has been banned for sale to Koi hobbyists, but it turns out - it's easy to make your own! Here is an excellent article on how to do it.
Someone asked that question to the Fish Vet - Dr. Richmond Loh in Australia. The answer may surprise you!
Read this fascinating article about the new research... There are definite implications here for Koi growth rates...
We are constantly reminded not to feed our Koi too much - both for the sake of Water Quality, and for the health of the Koi. And this time of year, some of us are not feeding at all because the water temperature is blow 50 degrees. But is it possible to feed the Koi too little?
As Koi keepers, we believe that most Koi food has been developed with the nutritional needs of our Koi in mind. But scientists are finding out that there may be a big difference in the nutritional needs of wild fish vs. fish kept in captivity, and perhaps the nutrients in Koi food will change in the near future to make it even more nutritionally beneficial.
!If you're not havin' FUN, you're not doin' it right