||Do I need expensive fish and plants such as Koi and tropical water lilies?
Koi are beautiful, but plain ol' Goldfish work just as well. Economical oxygen generating plants such as from an aquarium are all that is necessary. Winter hardy Water Lilies, or Cattails, as well as tropicals such as Water Canna Lilies, will add tremendous enhancement, both biologically and visually. It can either be a simple pleasure, or a water gardener's paradise.