Fish eat live food in the wild. And since they have adapted to this lifestyle over millions of years, they will always do better if they are given at least an occasional treat of live food.
There are a few instances in a fish's life where live food is more important, mainly when they are small fry and need a lot of nutrition and again when they are being conditioned for spawning. Most other times fish will do ok without live food but there is never an occasion when clean, disease free live food wouldn't be better for the fish's health.
If live food is out of the question, "ain't gonna happen in my house", then frozen foods are the next best choice. But I can tell you from experience that you just aren't going to be very successful raising fry without live food.
