China specifically raise all kinds of live foods like blood worms,
black worms to feed the pond raised fish. they power feed them
species appropriate foods to get them large very fast. Ingrid

That reminded me of something I wanted to bring up. So I changed the
Subject to reflect change. THIS IS NOT ABOUT type of FOOD per se. ;o)

Excuse some blanket statements below:

growth rate. Koi in small spaces do not grow as fast as a koi in a
large space in normal situations (feed, lots, often, pristine water and
they will grow fast). Now the koi in a larger space not only has better
water, but has all the good natural food growing, falling, crawling, flying
into that larger space.

What I've noticed recently. People who took some of my baby koi, when they
were 2-4 inches, and put them in a large space and thus they grew faster
larger koi than their siblings here, have more washed out colors. Hmmmm?
Comments?

Btw, the hobbyist feeds pretty much what I feed mine. ~ jan
~ jan/WA
Zone 7a

Jan I have heard (via internet) from Koi hobbyists that if the Koi grows fast, then it will achieve it's color potential later. Vice versa for Koi that grow slow. 1 of my older Koi is very faded, while 2 have kept their color, with one being more beautiful then he has ever been. So I suspect genetics play the greatest role, if the Koi are kept in good conditions.

I still think it is mostly genetics regarding color. Unless of course
you have access to one of the ponds in Nigata province in Japan in
which to overwinter your fish(and hope it will be found and returned to
you in the spring.) Good water is always important to clear colors, but
nothing guarantees it. I have what was supposed to have been a
Dianichi kohaku, that lost all of its color, and is very small for it's
age. We do have some 26" koi, so it's not pond size alone. This guy is
only about 12", and is the same age or younger than some of the big
ones, aprox 8 - 9 years old. I give up, I just enjoy them and accept
what we get!!
Olde Hippee