reefing102,
The gender of the African Butterflyfish is very difficult to determine. During spawning the males tend to have a convex anal fin with the central rays forming a tube, while that of the females are straight.
The male Butterflyfish are generally larger than females with a hump on their head and may also have longer fins than the female. Though some females may grow a hump on their head, it is typically not as large as the hump of a male.
If you have further questions please contact us.
Joyce F.
LiveAquaria
Drs. Foster & Smith