Goldfish tend to be high in fat so you ought to try adding some minnows or guppies to the diet rather than just goldfish all the time. Too much fat in the diet & they can have health problems just like humans who get too much fat in the diet.
If you are keeping live food in the tank most of the time then I wouldn't bother feeding them on a set schedule, although giving them some variety is good for them.
-----
PHRatz