I feed ours algae wafers and/or shrimp pellets 3-5 nights a week, then the day before a water change he gets his veggie--usually a slice of zucchini, half a brussel sprout, or a piece of spinach. If anything is left in the morning, it gets sucked up the vac during the water change and no one gets fed that day. He also eats any of the leftover food from the other fish (flakes, frozen worms/larvae/brine shrimp, etc). Any veggies I have for him are kept frozen so they last awhile and blanched to thaw and allow them to sink.
BTW, he's my favorite (and oldest) fish. He LOVES brussel sprouts so he helped me understand why they exist! Lol ?