And exactly how many did he keep? Any exact figures?
The only difficulties I see in breeding any Aro/Channa is the fact that you have to have an established pair and that can only be done by letting the fish do it by themselves. Again, that will need quite the number of individuals. Also, I really don't know whether one could have pairs when there are other species of fish there. That or it becomes inherently difficult if you don't raise Aros together.
BTW, I apologize for the lack of info. But BTW, Aro communities normally don't house more than 12 fish at most in big aquariums. And I'm sure that the cramptness/the fact that these fish would come from different sources, would not be in favor of most Aros comms.
Also, you failed to specify which Aros these Filipinos are keeping. I can claim to have an Aro comm and have the stock list consist of 1 or 2 of each Arowana species from across the world.
Also, the sayings of 1 keeper doesn't exactly end everything. It simply hasn't been attempted yet. And even these rich Filipinos would probably only want to pay for a big aquarium/pond at most. Simply put, either no one has attempted or anyone who has may simply have just not released anything to public.