|I want to know if it is advisable to have a small water garden which is mostly in the shade with little to no direct sun.|
|You can certainly have a water garden in the shade, but you may have trouble finding shade-loving aquatic plants. If plants are not important to you, set your garden in the shade. If you want flowering plants such as water lilies or marsh marigolds, you'll need to find a spot that gets at least 4-6 hours of direct sunshine.
Best wishes with your water garden!