Lily pads are a natural element in most ponds. They help to oxygenate water, offer cover for aquatic life and support amphibian lifeforms. However, when lily pads overtake the surface of a pond, they use up oxygen needed for other pond life, including fish. If you have a fish pond, be sure lily pads cover only 30 percent to 50 percent of the surface.
If you want to kill lily pads without harming fish and other wildlife, Texas Parks and Wildlife Department aquatic vegetation biologist Howard Elder suggests you rake out what you can. Lake rakes, which are longer than a yard rake, allow you to remove lily pads without wading into the pond. Such rakes are available at many sports and outdoors stores as well as department stores.
Many pond owners turn to products containing glyphosate, which include Shore-Klear and Aquastar, both of which are registered with the Environmental Protection Agency. Such products can be mixed with detergent and applied to lily pads with a sprayer for spot treatment. Spray carefully to avoid the chance of decomposing plants passing chemical gasses onto remaining plants. Spray portions of the pond, waiting one week between each section, and rake off dead vegetation each time.
Young grass carp, which feed on aquatic plants, can help control the spread of lily pads in a pond. Introduce three grass carp per acre in your pond. Because younger carp eat more than older carp, be sure to add young carp each year until they begin to repopulate on their own.
When all else fails, or when you don't have time to tend to your own fish pond, consider hiring a pond management company. Be sure to hire a certified company.