Pond plants play an important role in your ponds eco system. They help to provide oxygen for your fish and add balance to your pond water. They also compete with algae for nutrients in the water. In addition, some plants can actually help filter your water. Plants like water lilies provide shade for your fish and other plants provide a home for your fish to lay their eggs in. Aesthetically, they also will serve to help your pond blend in with the rest of the garden. No backyard pond should be without aquatic plants.