Kept the tank as shown for about 6 months, removed the TT eel and added cardinal tetras. Eventually had to move the aro as it needed a larger tank.
Still have the arowana, near 24" and in a 450g tank. The TT eel is about 27" now. Sold the discus and moved the plants to a smaller tank. As I acquired more tanks less time was available then I wanted to spend maintaining the planted tank and discus.