There's been a lot of press about Aquaponics and sustainable fish farming cropping up lately, so I wanted to share this astonishingly beautiful example:

Sepp Holzer lives on a mountaintop in Austria, where he casually but thoughtfully manages a fish farm that provides all of his food, clean water, income, and electricity through nothing but a series of carefully placed pond systems. Gravity pulls the water from pond to pond, and little micro-organism-eating fish are gradually replaced by bigger and bigger predatory fish until he has clean water and full-sized trout! It's so simple it might seem like magic, but it's actually cooler than that.

You can watch another short profile about Holzer's paradise here, and go here to see Eco Film's entire series on Permaculture.