When it comes to fish tank lights, you are almost invariably better off if you follow the golden rule of fish tank construction. And what is the golden rule?
Use all organisms that would normally live in the same ecosystem and recreate a mini version of that exact same ecosystem. This means that even the fish tank lights must match up with that of the original ecosystem.
Let's say, for instance, you are planning to recreate a tropical setting inside of your aquarium. If your fish live near the surface of the water in the tropics, you will want to provide a tank that is not only warm, but affords a sufficient amount of light.
Fish tank lights might not be enough, either; you may want to put the tank near the window, so it can get natural sunlight.
In contrast, let's say you are trying to recreate a deep, cold-water, high-salinity setting. You will want to use a type of gravel and salt that would normally be present in such an ecosystem.
You will also want to use a fish tank cooler to keep the temperature low. In addition to this, you may want to mitigate sunlight as much as possible. If the fish are used to murky, deep water, their skin may be somewhat sensitive to light.
So what options do you actually have for fish tank lights? One type of fish tank light will actually go over the aquarium.
These are usually fluorescent lights, which are affixed to a sort of cap for the tank. Other models, such as the ones from the BioOrb company, are actually part of the fish tank itself. They lights are installed below the gravel, releasing light rays when they are switched on.
Whatever lights you purchase for your fish tank, keep the golden rule in mind.
More Aquarium and Fish Tank Info:
Aquarium & Fish Supplies (home)
Cleaning a Fish Tank
Gravel for Fish Tanks and Aquariums
Fish Tank Maintenance
Fish Tank Pumps
Aquarium Screen Savers
Aquarium - Fish Tank Stands