I think if I had a Benjamin Graindorge and Duende Studio designed Floating Garden, I might actually allow my kids to have fish pets.
How great is this 100% natural water filtration system for aquariums based on hydroponics? Using the same science as Eco-pools, and natural systems in real ponds, the plants sit in a cushion of sand above the aquarium that naturally filters and cleans the water. The result is a cross between a decorative glass vase and a water purifying plant.
found via Ian Claridge
The floating garden uses two techniques for eliminating nitrate wastes voided by fish; Gravel-bed filtration which uses the sand bed to trap suspended waste and aquaponics whereby the roots extract nitrates to sustain plant growth, leaving the water returning to the tank pure.