I have 3x 12+" oscars in a 700g pond with a 24+" jardini and the oscars get hammered constantly by the jar- but even before the jar became their roommate 6 months ago, the oscars were intolerable of each other- I have a bunch of flowerpots and rocks in the pond as shelter for them- but as soon as one of the oscars comes from hiding, if the jardini doesnt nail him, one of the other oscars do- and at full aggression just like the aro does- I know that jardinis are the most aggressive arowana, but I also know greens and banjars are right up there with jars in aggression
I also have a 15" black arowana with a 12" florida in a 220g tank, and they often swim at the same level, but are almost completely oblivious of each other- but Ive also found blacks to be among the softest of the arowanas in aggression-
I dont know if that helps, because each fish and situation is different- but I can tell you that its what happens in my pond and one of my tanks