Water lilies ? or Nymphaea, to scientists ? are considered by many to be the jewels of the pond. Not only are they beautiful to look at, but they also serve an important purpose in the pond, mainly in aiding its ecosystem. Water lilies spread across the water?s surface, filling it with color and vibrancy all the while keeping the pond and the creatures in it safe and healthy. produce. Besides being pleasing to the eye, water lilies do a great deal to maintain the well-being of the ponds they inhabit. For one, they provide shade to keep the water temperature down during the hot summer months. By blocking out a lot of sunlight, the lilies help to keep the algae growth down. Their shade also gives shelter to any fish that may be in the pond ­? a respite from both the sun and any predators that may be lurking nearby. They also absorb nutrients in the water that would normally feed these undesirable green plants, keeping the water clear and clean-looking.