Here are the basics you will need to create a container water garden:
A water-tight container such as a planter, water trough, galvanized metal tub, or a half whiskey barrel. The ideal minimum dimentions are at least 1 foot deep and about 18 inches across. For healthy aquatic plants your container should hold 5+ gallons of water.
Submersible fountains if desired. See more on fountains here.
Complete your water feature with ornaments, plants, lights, and fish.