I used to feed my fish once a day, skipping the seventh day also. Now I feed once every two days. My tanks are much cleaner come cleaning time and my fish don't miss the daily feeding. My fish never begged for food, or if they did I simply ignored it (as a "parent" of fish, cats or children if I ever had them, no means no, and no amount of begging will alter that, so they can beg all they want. It won't change the fact they are getting fed when I want to feed them). I never fed my fish twice a day. To get around to feeding day-feeding and night-feeding fish I simply feed about 5-10 minutes before lights out. That way the day feeders get food in the day, and the night feeders still have food to eat when they are more comforatable eating. I have watched my fish and have learned the proper amount to feed to ensure everyone gets enough to eat, and that there is very little, if any, wasted food.
\Dan