Neonicotinoid contamination in aquatic ecosystems: A comprehensive review of toxic effects, underlying mechanisms, and mitigation strategies with implications for farmed teleosts

Neonicotinoids (NNIs) are the most widely used class of insecticides globally, characterized by high insecticidal activity and low acute toxicity to mammals. However, their extensive application has led to widespread contamination of freshwater and seawater ecosystems-via agricultural runoff, sewage discharge, and even indirect exposure through contaminated feed. Teleosts, as key aquatic organisms in both natural ecosystems and aquaculture systems, are inevitably exposed to environmental concentrations of NNIs. This review systematically synthesizes the toxic mechanisms, multilevel adverse effects, and potential detoxification strategies of NNIs targeting farmed teleosts. Key findings include species-specific toxicity profiles and multi-pathway detoxification strategies. It highlights specific toxicity data of representative NNIs, metabolite toxicity, temperature-dependent effects, and transgenerational risks, and reviews detoxification advances focusing on low-cost, aquaculture-compatible methods. Although direct evidence from farmed species under production conditions remains limited, this review synthesizes available toxicological data from laboratory studies (including model organisms and selected farmed teleosts) to provide a mechanistic basis for NNIs risk assessment and to identify priority research needs for aquaculture applications.