Live plants are valuable in an aquarium, just like they are in the home and outdoors. They absorb carbon dioxide and emit clean oxygen. If you planted live plants in your aquarium, you now need to take care of not just the fish and other aquatic life, but also the plants. Fortunately, taking care of the two go hand in hand, and other than pruning, plant needs are the same as fish needs: a clean tank, adequate lighting and a good balance of nutrients in the water.
Keep your aquarium clean and discard dead fish as needed. A clean fish tank will help keep your plants healthy. Clean the filter as recommended by the manufacturer and change the water with room-temperature water as necessary. Snails and other algae-eating fish or creatures will help keep your aquarium clean.
Maintain the correct amount of light. As a general rule, you need 2 to 3 watts for every gallon of water. An aquarium top with fluorescent tubes is the easiest way to light your average-size aquarium. For deeper aquariums (more than 20 inches), use mercury-vapor lamps rather than fluorescent tubes, at a rate of 6.25 watts for every inch of water. Too much light and you will soon have a tank full of algae. Too little light and your plants will begin to fade.
Keep an eye on your plants. If they begin to yellow quickly, the water may need more sulfur, iron or nitrogen. If you notice yellow spots or a lot of algae, the water may contain too much iron, phosphorus or another nutrient. Take a sample of your water to a pet store to be tested. You may need to add nutrients or an algicide to your water, or you may need to start over with fresh water. The pet store will give you a course of treatment based on your results.
Prune and thin your plants in order to prevent overgrowth. Plants can also grow so tall that they spread on top of the water, covering up the much-needed light. Cut off the tops of the plants so that the lower leaves will receive light, and thin the outer branches. Pinch the plants with your fingers or use a small pair of clippers. In addition, prune off damaged or discolored leaves. Remember, if you notice a more-than-usual amount of discoloration, take a water sample to the store to be tested.