I've read a few articles about what type of bulbs and/or setup to use in order to create a soft, moonlit effect in your tank at night. Many of them are expensive, complicated or both. I tried something the other day, however, that is CHEAP, EASY, and looks great. I went to Home Depot and bought an under-cabinet flourescent fixture with bulb included for about $10. I then went to Michael's craft and hoibby store and bought two rolls(one blue and one purple) of this stuff called Clearphane. I layered the colored celaphane several times until it created the desired degree of brightness. I then taped the material over the plastic housing already covering the bulb, mounted it to the hood of my canopy and now I have a soft bluish purple light in my tank for nightime viewing for less than $15. You can easily experiment with different layers and colors to create a totally custom look...experiment and enjoy the nocturnal activities of your fish