ubmerged water plants are also known as oxygenating pond plants because they actually filter the pond water. Submerged plants also keep algae growth under control and provide oxygen. Submerged plants grow fully immersed in water and get their nutrients from the water through their leaves, not their roots like other plants. Plants that grow completely under water provide shelter for fish, oxygen to the water and filter out pollutants.
Read more at Gardening Know How: Submerged Water Plants – Choosing And Planting Oxygenating Pond Plants