So guys it has been a week or so since I changed the fish to his new home. One weird thing I noticed is that he is now not the same anymore..he more frequently sits in the bottom...what could be it?
It can be water temp, new tank isn't fully cycled, he went from Your 20 gallon and I remember your fish was sittin on the bottom there as well. Any videos or pics?
How much of that new tank water is new water. It could also be him getting accustomed to his new surrounding which is kind of odd for Arowanas. The are a very active fish.
Young aros, in nature, prefer to occupy areas with some overhead cover. Float some driftwood and/or some plastic or live plants while he's adjusting to his new environment.