Any time with a cold water tank that i go with LED there are usually two options i pick from one is use LED lights and florescent with a small heater or i say screw LED and go with a dual bub florescent with a UV bulb too but to put your LED unit in there depends on how big the tank is and how far from the water level it is, the pet store by my place sells a 80w digital unit that can simulate tropical sunlight its so bright, even thunderstorms. but if you are scared of blinding your fish use a piece of smoked glass or frosted glass to help diffuse the light. i have a 2.5 gal breeder tank for my fry and they love the LED light it has. but try florescent first a good unit will give a more even and healthy light spectrum than LED can unless you spend <300$ on the light system