In my 2,000 square foot minnow pond, I stocked probably 250 Rosy Reds along with about the same number of common FHM in early March 2016. Now, there are very few Rosy Reds left. There are no predators in the pond. I think the common variety is dominant and the "Rosy Red" breeds out after a couple of generations. The pond has very limited visibility, maybe 4-6", so bird predation is not a problem. I am going by what I find in my minnow traps.