Proper aquarium aeration is one of the most important things to consider in setting up any aquarium. Low oxygen levels are more common - and dangerous - than often realized. Use an air pump to bring fresh oxygen into your tank and power certain equipment. Add air stones to aid in circulation and create beautiful displays of shimmering bubbles.
If you have a large tank, consider supplementing your aeration system with a water pump or powerhead that will aid in properly circulating the oxygen through your entire tank.