Ikea sell a product called "Dioder" which is a set of LEDs on three strips which change colour. They have a plug attached and can be mounted very easily to the hood. There are videos on you tube.
Also many companies sell blue led
strips which come with suckers and plugs attached which are good moonlight subs. Or there are single LEDs which are attached to a hub and can be placed different areas in the tank. All outdoor lights are water proof so any outdoor specific light or light fitting should be fine as long as the plug is kept dry.
Lots of choices if you look around. I brought an 18 led
strip with suckers, and I'm very happy it cost less than £10/$15 roughly, is very bright, and you can move it from tank to tank with no setup hassle.