This debate is easily solved. Does anyone have a kid around 12 years old?
If so buy them 2 tanks, place an Asian arowana in one and a convict cichlids in the other. Leave the fish totally in the care of the child then Post an update in 12 months of how they are progressing. I know what I would be betting would be in better shape.
Also the OP has now moved on from this, it looks like he has taken at least some of the advice that has been offered so I don't see the point of trying to prove it one way or the other anymore.