N&K, take a close look at Optimal brand feed.. Read about it, study it, ask questions.. I have a couple of Hunting trial Dogs at all times and I feed some expensive food for those beggers.. I look at it this way, a wise man (Bill Cody) once wrote: "a fish only has so many heartbeats-how it grows during that time is important because at any time it's lacking what it needs, it never gains it back".
If you think of it that way, I don't see it so much as expensive, I see it as an obsession to grow the biggest, most healthy fish possible.
I might add one more thing.. In a pond surrounding, "easy to catch" and "Big fish" don't always go hand in hand, but don't let that slow you down, the rewards are well worth the effort!
If you search, I think it was shorty (Maybe?) that posted some ideas on screening off some areas to raise certain fish. Keep in mind you're feeding a LOT of fish for a very short time (days)for what you may be able to produce in a small area with a pond as big as yours.