With the silver arowana we had grown from babies and those we had rescued early on, I wasn't paying attention as they were growing up. Only once they started breeding for us, as a surprise, did I start attempting to see if I could tell males from females. The half a dozen rescue silver arowana that have been coming to us in the recent years at 1'-2' all have had long pelvic fin extensions, which I don't know yet how to explain - whether they have all been females accidentally or whether the fin length changes only after reaching sexual maturity.
BTW, I have not analyzed the A crease, which could have been my oversight, inconsequential of not, IDK. The A crease doesn't seem reliable from the reports of others, including that photo of the Asian arowana you posted.
As for this video, we don't know which arowana laid these eggs to be sure at least that that particular arowana is the female. The first appearing arowana has longer fins indeed, the other has the fins on the border between long and short, so I'd not be so quick in saying both are females. The non-egg-layer could have been an immature male. Or, alternatively, laying eggs in a 55 gal tank is kind of strange for silver arowana, exceedingly little room, so the male might have been too stressed to fertilize the eggs and take them in the mouth, or stunted, or else... That is if the other is a male. If a female, then it is also and easily understood.
