Around here the preffered pond stocking is a mix of bass, blugill and channel catfish. You have to maintain the correct ratio of about 5 bluegills to every one bass. Catch and release the bass. Catch and eat the bluegill. You can almost never overfish the bluegill. It is unlikely that the catfish will reproduce, unless you provide them with clay tiles or similar structures to hide in. They don't recommend the open water species such as perch or crappie in ponds under 10 acres.
As far as how many fish will a pond support, they figure it like this... A pond has the ability to support X many pounds of fish. Lets say 100 pounds as an example. It will support 1- 100 pound fish or 10- 10 pound fish, or 100- 1 pound fish, or 1000 1/10 pound fish(they keep getting smaller). That's why its important to maintain the bass to bluegill ratio. The bass keep the bluegill in check. The bass provide good sport fishing and the bluegill provide good eating.
Also highly recommended is a way to drain the pond for maintenance or fish population corrections.