You might wanna close the curtains or shoot at night with the tank light on...the reflection of the neighbors, your head and camera make it really hard to see the Arowana...try shooting at a 45 degree angle from glass, this will take the reflection out of play...
It is also hard to tell anything from the overhead shot without something to compare or "show size perspective"
you have a sub adult Arowana there, and it has the genetic disposition to get 30"+
Judging from the pond comment in your signature, there is a size issue with his tank.
What size of tank do you have him in now?