Insecticide-induced oxidative stress in aquatic animals

Insecticide contamination of aquatic ecosystems poses significant risks to non-target organisms. Oxidative stress is a commonly observed physiological response in aquatic animals exposed to insecticides and reflects disturbances in cellular redox homeostasis caused by multiple interacting toxicological processes. This review summarizes current evidence on oxidative stress responses induced by major classes of insecticides in aquatic animals, including organophosphorus insecticides, pyrethroids, organochlorines, and neonicotinoids. Rather than treating oxidative stress as a single biomarker or an isolated primary toxicity mechanism, we define it as a physiological redox imbalance and an integrative downstream response that links class-specific toxicological targets with cellular injury, organismal dysfunction, and potential ecological risk. Changes in antioxidant enzyme activities, lipid peroxidation, and redox-related biomarkers reported across different aquatic taxa are systematically compared. By synthesizing insecticide-specific evidence, this review highlights the value and limitations of oxidative stress- related biomarkers in aquatic toxicology and emphasizes their role as supportive indicators for interpreting toxic effects and environmental risk, while acknowledging the need to integrate them with more specific mechanistic endpoints in future studies.