If there is limited predation, the rosey red genes may display more regularly.

I stocked my 0.34 acre experimental forage pond with 100 FHM. 90 were rosey reds, 10 were the natural coloration. In one year to population was 50/50 with no fish predation. By year two with the introduction of HSB and albino CC, the population had flipped to 90% natural, 10% rosey red. Almost 3 years in it's extremely rare to even see a rosey red. I think I saw two last year but still have thousands of FHM.