you have alot of options, just cut and dice to the desired size for your particular sized arowana.
Feeding:
the Silver Arowana is a pure carnivorous fish and will take a variety of meaty foods.
The most important thing is to get your fish on a high quality commercial diet of pellets or food sticks, This should be the staple of the fishes diet, avoid goldfish as they have a high fat content, contain an enyme that inhibits the absorbtion of thiamin and can carry diseases & parasites.
Live feeders are a good food source given that they are quarantined and gut loaded, now when I say "gut load" I don’t mean buy them stuff the heck out of them and then feed them. To get the best out of your feeders, instead of feeding them prior to feeding your predators, wait a little while, let the feeders grow and bulk up. Feed a high quality commercial food and keep the water as pristine as possible, you increase the nutrient potency of the fish by letting them “fatten up”, not nessesarily making them higher in fat content, but make the fish grow leaner, stronger and healthier, once they reach this point you are ready to feed them out, also a healthy feeder will be full of energy and give your arowana literally an “run” for there money or should I say “exercise” . Silver Arowanas can eat a wide variety of foods: pellets, grocery store shrimp, krill, night crawlers, superworms, earth worms, scallop's, blood worms, tubefix worms (NO LIVE: these are collected from contaminated areas), rosie red minnows, various live fish such as guppies, sunnies (sunfish), mollies, crickets, various fish fillet (catfish, tilapia, halibut, etc) , squid, grasshopper (for larger arowanas).frogs, specifically bullfrogs, centipedes, crayfish and even pinky mice. Sometimes a little patients is required to get this fish to eat certain food items such as for example pellets. This can be accomplishes by periods of fasting until they accept the food item.
THIS ONLY APPLIES TO HEALTHY SILVER AROWANAS. Sick or malnurished fish may get worse or may not survive from fasting, a suppliment of garlic extract or other food enticer may get this fish to accept it's food. The idea is to keep the diet as varied as your possibly can (or afford), the purpose of a varied diet is make sure the fish is getting all the nutrients it needs that it’s not getting from a single type of food.