Does the day light bulb give off UVA/UVB or just heat? Unless you spent a lot of money on the bulb you will need a second bulb to produce UV rays. This is important so that the lizard can process calcium correctly, and if you plant live plants they will die without a UV bulb.

Also, since Water Dragons grow rather quickly, you will want to gut-load his food for at least 24 hours before feeding it to him. Keep the food in a separate container with lots of calcium-rich veggies to eat, it makes them more nutritious for the lizard. Calcium dust is helpful for growing lizards too.