Hi! I am new here, but I am not new to he fish hobby. I have currently an Albino Oscar(5inch), Severum(5inch) and an Ornate, Albino, and Senegal Bichir all residing in a 55 gallon tank. But don't worry, I've just been growing them out their, because soon I'm going to he upgrading to a 400 gallon tank(already cycling). I also purchased baby Silver Dollars(6), and 7 Geophagus. Those ones are still small and are in my other grow out tank. All those I plan to put in the big tank. I would most certainly like to add a Malaysian Green Arowana and a Black Ghost Knifefish. My main questions is that how long will it take for he Geophagus and Silver Dollars to reach around 4 or 5 inches? I'd like to time getting the Arowana perfectly to where he won't be eating them because the average size of them at the store is 6 inches. Also I would also like to know if any other fishes can be added and if there are some potential stocking issues regarding their copaibility based on aggression.