Sub-lethal Effects of Insecticides on Fish Behavior and Physiology

Insecticides, widely used in agriculture and public health, often contaminate freshwater ecosystems, leading to sub-lethal exposures in aquatic organisms, particularly fish. Unlike lethal concentrations that cause immediate mortality, sub-lethal concentrations induce physiological and behavioral changes that may not be immediately fatal but can significantly impair survival, reproduction, and ecosystem balance. This paper reviews the sub-lethal impacts of commonly used insecticides, including organophosphates, pyrethroids, and neonicotinoids, on fish behavior (such as feeding, schooling, and predator avoidance) and physiological systems (like respiration, enzyme activity, hormone regulation, and immune function). The study draws on recent experimental evidence from various geographic regions, with special attention to Indian freshwater ecosystems. Understanding these subtle yet significant effects is vital for environmental monitoring, fish conservation, and pesticide policy regulation