Freshwater systems surely play a key role in keeping nature balanced and supporting different living things. Moreover, these water bodies help meet important human needs like drinking water, farming, and fishing. Zooplankton work as main consumers in these systems and further connect phytoplankton to higher food levels. This connection itself helps maintain the food chain balance. As per their sensitivity to environmental changes, they work as good bioindicators regarding water quality. This study shows a complete review of research papers regarding zooplankton changes, seasonal differences, and water quality factors that affect freshwater systems. The focus is on how zooplankton helps in checking the health of water bodies as per ecological studies. As per the review, zooplankton groups like Rotifera, Cladocera, Copepoda, and Ostracoda show major seasonal changes regarding temperature, rainfall, nutrients, and water quality factors such as pH and dissolved oxygen. Summer seasons show higher zooplankton numbers due to increased nutrients and phytoplankton growth, whereas monsoon conditions further reduce these populations due to water dilution and turbidity itself. Winter seasons surely provide stable conditions that support moderate diversity. Moreover, these conditions remain relatively consistent throughout the season Moreover, physical and chemical factors of water surely control where zooplankton live and how many different types are found. Moreover, these parameters are considered the main drivers of zooplankton community patterns. Basically, changes in temperature, oxygen, and nutrients directly affect how these organisms survive, reproduce, and form the same community structures. The review actually shows that zooplankton are definitely good indicators for checking pollution and ecological problems in freshwater bodies. These small water animals can reliably tell us about environmental changes. Basically, the study found major research gaps - there are no region-specific studies, no combined biological and chemical analysis, and the same lack of long-term monitoring in freshwater reservoirs like Sathnala project in Telangana. The results definitely show that water quality management actually needs to include zooplankton studies for better conservation work. This review surely gives a complete picture of how zooplankton changes, seasonal patterns, and water quality are connected. Moreover, it shows why these connections are important for managing freshwater ecosystems in a sustainable way.