If you do this maintenance and repot the plants each spring, completely emptying your water garden is generally not required. Even healthy, well-balanced water gardens may turn green in late spring. However, as the lily pads cover about ninety per cent of the water surface, this green algae bloom soon fades away and the water clarifies. Goldfish add both color and movement to your water garden. Goldfish also eat many types of filamentous algae before they become a problem.
Aeration is vital to the success of any water garden.
Therefore, a submersible pump should be installed to provide proper water circulation. A small waterfall feature would provide both aeration and the relaxing sound of splashing water. Aeration also prevents undesirable odors from waste materials always present in these situations. While the aeration is obviously beneficial for the goldfish, it is also helpful in the breakdown of the waste materials we discussed earlier. Ideally, the depth of the water garden should be about two feet.