I usually feed my fish as often as I can but make sure they eat all the food that I stick in within a minute or 2, obviously if you are feeding more often then you feed less each feeding. As long as there is no uneaten food then you can't really go wrong. If you feed more often your fish will grow faster and produce more waste so that might be a consideration.
As much as what fish NEED they probably only need 1 feed every day or 2, I would be inclined to feed your tank relatively often to try and save your smaller fish from getting eaten by your angels. Might be a bit futile but is worth a shot..