mine are only really hungry when they start trying to jump to the dry food can sitting on, otherwise they are like a cat and a fridge, ie try to look hungry everytime you go near their tank.
I hand feed all the big fish once a day, it allows several things, lets me inspect each one individually, lets the smaller fish, (yup I keep small cichlids in with the oscars)get a feed in peace. I keep adult firemouths and severums in the tank from time to time to stop them from breeding. It also seems to to stop the female gold severums from getting beaten up by the single female green as they are so busy schooling to think about pairing up. The oscars are reasonably peaceful and I add freshwater shrimp in the tank every now and then for some extra interest.