Create a balanced pond with Vallisneria, the Aquatic Grass plant
https://spark-wiki.win/index.php?title=Koi_as_ecosystem_engineers:_enhancing_biodiversity_in_your_Pond
Creating a Balanced Pond with Vallisneria: The Aquatic Grass PlantIntroductionOverview of VallisneriaVallisneria, a submerged aquatic plant