Prawns wouldn't be a stable food, at best maybe a treat every now and again. Hikari should be fine as a main, if that's whats in you're mean of being able to feed the fish. If income was tight, i would've chosen a different fish myself. You are yourself and you know what you like and i can't and wouldn't take that from you. Earth worms, cricket and grasshoppers can be caught outside, no cost there. A arowana can eat most insects you can find outside. Also lizard and frogs!I can afford only prawns or hikari sticks . Will it be good feeding prawns every day ?