i have bred koi before. im not a amateur. And the blue one is a female. you cant tell from the picture either, your "quality" koi you seem exactly the same quality as mine.
you cant breed koi at 20inch as the eggs in the female might not take right as they are to old. the proper koi breeding size is 12 inches or more. Bc they have matured at a good age.
all im asking is a opinion not a negative comment. btw your pictures are taking in High definition so yours look cleaner. mine was on a crappy phone.
So who told you that you can't breed koi at 20 inches? I guess the biggest farms all over the world are not breeding koi with there breeders that are all larger than 20+ inches. How about you make a phone call to some of these farms and and ask them how big there breeders are. I can tell you Hanover Koi, PA, his breeders range are large some close to 36 inches, black water creek FL his breeders are also 36 inches, smaller farm sundan koi in FL, his breeders are large 24 inch plus, so tell me why these people at these farms are you using such big fish to breed. You can find pictures also posted on the internet of some of these farms larger koi. The larger the fish, the more mature the fish is. Koi live for a long time, so a 20 inch fish is not old at all. 12 inches is very very very small for breeding, the fish is still going through a growth stage and maturing, just like humans goes through puberty. Also sexing a fish can be done by looking at the fins and body shape if it is a standard fin koi. People that have been around koi for a long time, are in the hobby for competion, or that just know koi and buy lots of them, can usually sex a fish as small as 6 inches, but it becomes alot easier when they are bigger like you said. But at 8 inches you can sex them and be about 80% correct if the fins are real nice and not beat up. Good luck on breeding them, and if you have breed koi before, i would like to see pictures of them and pics of the off spring.