Hi, thanks for your question. The first thing to do, is to buy a test kit, which will enable you to check the levels of ammonia, nitrate, and nitrite. Many times, fish who appear to be gasping for air, are actually being harmed by toxic levels in the water. The safest and most efficient way to oxygenate the water is to add live plants. An easy species of plant is Anacharis, which is available at most pet shops. It will scrub nitrate, and nitrite, from the water, and add oxygen.