The ideal garden pond is one that has a natural and harmonious balance. This can rarely be achieved where the reflective quality of the water is its paramount attraction, or where major moving water features play. However, in the traditional well-planted garden pond with its modest complement of fish, it is a realistic and long-lasting proposition. It is essential that every component involved achieves harmony from the beginning.
When looking at the principles of natural balance it is clear that there are two important aspects that require immediate consideration - the provision of abundant underwater growth and surface shade. Submerged plants perform an invaluable and often diverse role. Their main task is to mop up nutrients in the water and to release oxygen during the day to sustain fish and other aquatic life. They are also to some extent a food source for fish and often serve as a nursery for fish fry. So they clearly have a major impact upon a pond's ecosystem. By removing excess nutrients from the water, submerged aquatics deprive green water-discoloring algae of the opportunity of becoming established.