Unless you do what I do!.... which is limit the number of fry (I never had more than 5 babies in one year) by removing anything the eggs could hide from getting eaten (that's why I keep plants in a separate pool) and re-home any baby that regardless my effort still manage to be bornThing is once they breed they will be mixed and no way to say what fish you have .I know I have koi mutts ,lots of koi mutts .Koi also need lots of aeration in the pond
..but just because I can manage my pond this way, doesn't mean it would work in another pond