Asian Journal of Fisheries and Aquatic Research

Background: Mancozeb and propiconazole are widely used agricultural fungicides that can enter freshwater bodies through surface runoff and may affect non-target aquatic organisms. Clarias batrachus, a freshwater catfish of ecological and food-fish significance, is frequently associated with habitats exposed to agricultural effluents and provides a suitable model for cytogenetic assessment because of its nucleated erythrocytes. This study protocol outlines an approach for assessing the genotoxic potential of mancozeb and propiconazole, individually and in combination, in C. batrachus. The proposed design includes acute and chronic exposure scenarios, sub-lethal concentrations derived from LC₅₀ values, and biomarker-based evaluation of DNA damage in blood, gill, liver and kidney tissues. The principal endpoints include the alkaline comet assay, micronucleus test and chromosomal aberration analysis, supported by oxidative stress markers such as SOD, CAT, GPx and MDA. Molecular analysis of DNA repair and stress-response genes is also proposed to clarify possible mechanisms of toxicity. The protocol further emphasises environmentally relevant exposure conditions, mixture-toxicity assessment and standardised sampling procedures. The expected outcome is a structured framework for generating species-specific evidence on fungicide-induced genotoxicity in C. batrachus. Such data may support aquatic biomonitoring, ecological risk assessment and future management of pesticide contamination in freshwater environments.