Breeding Butterfly Koi

I got a pair of butterfly Kois with metallic gray color but they are relatively young (about 4months old) and I wanted to breed these guys. When is the right age for Kois to breed? -Gio Koi start breeding when they are at least 2 years old and when they are at least a foot long. I'd say that with two Koi, you have a 50/50 chance that both might be the same sex or that you have a male/female pair. If both of them are male or female, then you'll never be able to breed them. Share: Del.icio.us Digg Reddit