The main aim of a Japanese water garden is to provide calmness and harmony. They also render values that are spiritual and also express Japanese philosophical principles by way of mixing together of needed elements such as water, stones, ornaments and bridges. The placement of each of these elements has its own reason when it comes to Japanese water garden.
As far as the maintenance of these water gardens you need immense time and energy to be spent on them to make them look fresh and neat unlike any other gardens. And that water garden is Japanese water garden, and then it will actually double when it comes to maintenance.
In any water gardens the colorful fishes add extra bit of beauty to them and hence require frequent change of water to keep the fishes from acquiring any diseases. Most of these water gardens will develop into a beautiful natural gardens without any human intervention except the initial intervention but at later part will require more time to spent on them in terms of maintaining them.
Mostly nature will provide all its need for the water gardens except where human intervention is needed like pruning the trees and plants, cleaning water, removing all the debis, etc.