Fish and food

A look at some of the benefits of old farming methods.
http://permaculturefreepress.com/?p=515

The main one mentioned is using the water around rice paddies to also grow fish, which keeps pests down, and also helps add nutrients for the rice to grow with.

Considering that I'm trying to turn my pool into a pond, and that I hope to use the fish, at the moment, primarily for helping keep pests down and help fertilize fish,  this is of real interest to me

And I'm fascinated by this picture right here, even thought there is no description of what it is!
http://permaculturefreepress.com/wp-content/uploads/2013/12/1-RF-diagram.jpg