Mix varieties diet is the best since it practically train the aro to eat anything you throw in the tank and provide all the necessary nutrient for the fish; however, some aro will only eat certain foods, and some don't. The basic of the mix diet is pellets, frozen shrimps, live shrimps (if you could buy), mealworms, crickets, grasshoppers (if you could catch/buy). Other foods such as live fish (included goldfish), centipeds, crayfish, frog can be hard to find or little risky in term of transmit disease to your aro (goldfish). If you want to feed your aro with live fish (especially goldfish and wild caught), you need to quarantine them first. Hope it helps.
