Thanks for the replies everyone.
I think we will change the food and then wait and see for another year.
Bern did the problem resolve when you changed the food or once the Hi is up it stays?
Simon we appreciate the gamble taken with small koi but we get a lot of pleasure from watching the babies develop. Dreaming how the may turn out, sometimes we like to think we have got it nearly right. This one we bought at 7" Here is a photo taken 18 months later at just over 16"
http://homepage.ntlworld.com/david.h...2kohaku32.html