Butterfly Koi For Sale Sexing - How to tell a male butterfly koi from a female butterfly koi?
It is much easier to determine the gender of butterfly koi fish than it is for a goldfish. With that said, it is almost impossible to visually tell the difference betwen male and female butterfly koi if they are immature in age and size.
As butterfly koi grow, prominent signs of their gender develop. Male butterfly koi will have more elongated fins, while female butterfly koi have more rounded fins. Also, male butterfly koi have a more slender appearance, while female butterfly koi have a more oval body shape. Female butterfly koi fish will be full of eggs during spawning season, giving them a more blimp like appearance.