Water quality significantly affects fish populations, influencing their growth, reproduction, and overall health. Poor water quality, due to pollutants such as heavy metals, nutrients (like nitrogen and phosphorus), and pathogens, can lead to declines in fish populations and biodiversity. Fish require specific conditions for spawning and thriving, and changes in water temperature, acidity, or dissolved oxygen levels can be detrimental. Maintaining high water quality is essential for sustaining healthy fish populations, which, in turn, supports entire aquatic ecosystems and local economies reliant on fishing.