Definition
"Pond scum" is a general, informal term for the often unsightly layer of algae and other microorganisms that can accumulate on the surface of ponds and other bodies of water. It's a non-specific term, meaning it can refer to various types of algae, including Zygnema and Spirogyra, as well as bacteria and other organic matter. While it might look gross, pond scum is a natural part of aquatic ecosystems. It is most similar to the top layer of a neglected fish tank 🐠. However, excessive pond scum can indicate pollution or an imbalance in the ecosystem.