Put a background on put some tankmates in soon. Otherwise it is going to beat up anything you try to put in and claim his territory most likely. Background will really make colors come out unless your trying to create a real high shine aro then keep in a white tank. It may not eat for a few days or longer so don't panic
You don't need a background it's preference. But if you really want the gold and reds to stand out more a blackor blue background would make a big difference. . Feed a variety of diet. Try to get it on a floating pellet and some market shrimp or tilapia fillet. Silversides are good. I have read on other sites that mealworms are not a great diet and can cause harm in the long run. I don't know how true but have seen pics of dead aros cut open with stomachs loaded with mealworms When I fed mealworms I would cut the heads off. They are more of a treat I think.
Great fish bro...Pump it up and soon the colors will come out well. U can also try putting up a black or blue background as per ur choice
Take good care of it