You need a lot more plants and branches, to the point it is a little difficult to find him. This is probably the reason he is hanging from the roof of the cage. Also substrate can be dangerous depending on what you're using. fish being next to the cage could be adding stress too. If you got him at a pet store there is a good chance he wasn't properly taken care of. It's hard to say a chameleon is perfectly healthy because by the time they're showing symptoms things have gotten pretty serious.
Not trying to give you a hard time, but unfortunately there are a lot of veiled that come on here supposedly very healthy, but never end up seeing them into adulthood. Without these forums and extensive research we'd all be making mistakes so don't take it personally.