Well.. Cichlid vents (sexual organ) if MFK allows that word to show..
is determine by the shape of the vents... U shape, or round is Female.. and V shape, or a sharp point behind the anus is the male's vent...
thats usually how u can tell if ur fish is a male or female... Also.. when female laid eggs, tube gets VERY VERY long.. thus the U looking round shape..
I personally saw it in my Female Flowerhorn... there are pictures online about sexing your cichild's by the vents...
So i'm guessing it applies to EBJDs too.. since they are cichilds...