Good quality pellet, chopped fish talapia, smelt etc are good suggestions. I also am a big fan of insect feeders , Meal worms and super worms, ideally gutloaded with fresh veggies. IMO a varied diet always yields the best results.
Avoid too much frozen shrimp or cooked shrimp, cooked shrimp has poor nutritional value compared to raw, but once frozen raw shrimp is very high in thiamese which leads to calcium deficiencies. Also avoid mammalian meats like beef heart, arowanas cannot break down the fats which then build up on the liver.
Hope that helps.