If I ever have a pond with fish again I want to try it. It would probably drive my cats crazy though LOL (Use a heavy glass vase and invert it on some concrete blocks so they can swim in from the bottom. Submerge the vase and turn it up under water so the vacuum created keeps the water inside. Make sure you have a heavy glass container or the weight of the water will shatter it.)
pond biofilter -- We're thinking of adding a small flock of ducks to the homestead for eggs and meat. With that comes the need for water. I'd love something a bit nicer and more natural than just a kiddie pool so building a small water feature is ideal. Adding a small DIY bio-filter system that can be utilized in the small pond, water plants (which feed on waste products in the water) furthers the eco-balance we are working towards.