Morpho-behaviour Changes in Fish Exposed to Malathion: An Ecotoxicological Study

Abstract

Behavioural changes are key indicators in ecotoxicology, revealing the impact of toxic environments on aquatic organisms. This study investigated the effects of malathion, a common pesticide, on the behaviour of Heteropneustes fossilis. Fish exposed to malathion showed significant behavioural changes within 30 minutes, including loss of equilibrium, erratic swimming, and increased speed. Morphological changes, such as skin discoloration, chemical deposition, and lesions, were also noted. Behavioural symptoms progressed with higher concentrations and longer exposure, leading to increased activity, air gulping due to hypoxia, and reduced resting periods. Severe symptoms, including lethargy, unresponsiveness, and extensive skin peeling, emerged over prolonged exposure. Acute toxicity testing revealed immediate surfacing behaviour followed by lethargy and signs of asphyxiation. The study concludes that malathion exposure disrupts normal behaviour, likely due to stress and biochemical changes, highlighting the pesticide's ecological impact.