Ponds and Fountains
When the aquatic flora and fauna are balanced, an aquatic ecosystem is created that will support sustainable water quality and clarity. Elements such as fountains, statues, waterfalls, boulders, underwater lighting, lining treatments, edging details, watercourses, and in-water and bankside planting can add visual interest and help to integrate the water garden with the local landscape and environment.
Water gardens, and water features in general, have been a part of public and private gardens since ancient Persian gardens and Chinese gardens. For instance, the (c. 304) Nanfang Caomu Zhuang records cultivating Chinese spinach on floating gardens. Water features have been present and well represented in every era and in every culture that has included gardens in their landscape and architectural environments. Up until the rise of the industrial age, when the modern water pump was introduced, water was not recirculated but was diverted from rivers and springs into the water garden, from which it exited into agricultural fields or natural watercourses. Historically, water features were used to enable plant and fish production both for food purposes and for ornamental aesthetics.
Though the term "water garden" is normally used to describe a particular type of natural or man-made water feature that is used for a relatively specific purpose, there are many other types, styles and designs of water feature.
Often the reason for having a pond in a garden is to keep fish, often koi, though many people keep goldfish. Both are hardy, colorful fish which require no special heating, provided the pond is located in an area which does not have extremes of temperature that would affect the fish. If fish are kept, pumps and filtration devices are usually needed in order to keep enough oxygen in the water to support them. In winter, a small heater may need to be used in cold climates to keep the water from freezing solid.