Heterobranchus: From the Greek heteros, meaning different and branchos, meaning fin; in reference to the presence of the two dorsal fins (rayed and adipose).
Sexing
The genital papilla, which is right below the anus, is elongated and pointy in males while it is round and relatively larger (and larger than the anus) in females. In ventral view especially, females are much broader in the body than males of equal age and rearing practices.
Size
Smallest 640mm, largest 1500mm, average 1135mm, most commonly 1500mm. All SL.