Most lights work just as well in freshwater as they do in saltwater. If you have a good light with your freshwater tank, you will not need to purchase new saltwater aquarium lighting. The only time you need to change the lighting is when you move from tanks with fish only to tanks that also contain live plants.
Best Saltwater Aquarium Lighting for Corals
When you change from freshwater to saltwater, your aquarium lighting may need to change if you are going to include corals in your new tank. Corals have very specific lighting needs and they should only be placed in tanks with adequate lighting. The best lights for corals are metal halide lamps. These lights simulate sunlight and allow the corals to perform photosynthesis, which is often used to supplement the regular food supply. They also need stronger light to spawn, which is the process that will give you more corals in your tank.