These plants absorb excess nutrients in the water, reducing the food available for algae. Feed aquatic plants with fertilizer tabs pushed into the soil of their pots once or twice a month. Hardy lilies need no special care. Floaters such as water hyacinths and water lettuce usually die down to winter buds, which sink to the bottom. Marginal plants should be cut back and brought inside to ensure survival.
Snails are also important to the health of a garden pond, as they consume excess organic matter.
Stock snails at the rate of one per square foot of surface area. Before introducing fish and snails to a pond, allow the bag they were sold in to float on the surface for a half hour before releasing them. Chlorine in the water kills fish and snails and is hard on plants as well. Use a dechlorinator after filling your pond for the first time.