Different aquariums require different lights. mini-critters carries one that is right for your aquarium

While that's true in a simple tank with just a couple of fish, it can get much more complicated as your aquarium gets more complex.

Beginner aquariums usually come with regular fluorescent bulbs - just like an under-counter light would contain.  This is adequate for a simple aquarium with just fish.

If you add any plants, though, the light won't be enough for them to thrive.  Saltwater aquariums require even more light and reef tanks with live coral and anemones require incredibly bright lights...

mini-critters has the right bulbs for your aquarium.  Here's a list of the types of bulbs used in aquariums:

1. Regular Fluorescents at 15-40 watts
2. Power Compact Fluorescents use 10-100 watts, but run much hotter
3. HO (High Output) Fluorescents require a T5 fixture and use 20-60 watts
4. VHO (Very High Output) fluorescents use 75 to 160 watts each and require a special VHO fixture
5. Metal Halide bulbs use 175 to 1000 watts and require their own fixture.

As you move down the list, you'll find that more cooling is needed and the price of the lighting, as expected, goes up.  However, the light produced by these bulbs is closer and closer to natural sunlight and that will allow more variety of life in your tank.

Since you simply can't change bulbs, but have to buy a new fixture with each step of the list, it's best to decide what kind of tank you're going to create in the long run, and buy your lighting  to match the end result, rather than change the whole system out multiple times.

While we're talking about lighting, we should mention that you need a timer to control how much light you're providing.  The idea should be to mimic  a day and night cycle, since your fish require both sleep and active times.  One important thing is to make sure your timer is big enough to handle the wattage of all the lighting you may be using.