I bought a Momotaro Kohak and a Gin Rin Marudo Kohak(Joe knows this Kohak well..
). The 2 bought at the same time and same lenght(5 inches) did not grow equally. The Momotaro is now 15 inches and the GR Marudo Kohak is 9 inches...Can't explain it...either...Genetics seems to be answer to this, but kinda weird you have the genetics and fish still turned out that way.