Here are the different ways of sexing your flowerhorn.
1. Difference in body shape and size.
Male flowerhorns are bigger than female flowerhorn. If you are selecting from a community of frys choose the bigger or biggest fry because the males are more dominant than females and stronger so they always have access to food which makes them grow bigger fast.
Male flowerhorn will have bigger koks than female flowerhorn.
3.Presence of black markings on dorsal fins.
Female flowerhorn will have black markings on the dorsal fins. These black markings will be evident even in fry as big as 2-3inches. It is accurate way of sexing 80% of the time.
5.Difference in body color.
Female flowerhorn will change in color when breeding time comes while the male maintains its vibrant color.
6. Difference of shape of vent area.
You can differentiate the sex of your flowerhorn by venting.
7.And lastly and most sure fire way of determining if your flowerhorn is male or female.