Dissolved fertilizers are water pollutants. When fertilizers are applied to land, some of the nutrients dissolve in rainwater and are carried into streams and other water bodies. The excess nutrients, especially nitrogen and phosphorus, can cause an overgrowth of algae and other aquatic plants, leading to a process called eutrophication. This process can reduce oxygen levels in the water, leading to the death of fish and other aquatic organisms.
Aquatic animals, shrimps, and water plants are not necessarily water pollutants but are part of the aquatic ecosystem. However, their presence and abundance can be indicators of water quality and the health of the ecosystem.