The pervasive use of pesticides in agriculture has led to the contamination of aquatic ecosystems, posing significant threats to non-target organisms such as carps. This review synthesizes current research on histopathological alterations observed in various carp species—including Labeo rohita, Catla catla, Cirrhinus mrigala, and Cyprinus carpio—exposed to sub-lethal concentrations of pesticides. Notable tissue-level changes include epithelial hyperplasia, lamellar fusion, and necrosis in gills; vacuolar degeneration and necrosis in liver hepatocytes; nuclear damage and tubular degeneration in kidneys; mucosal desquamation and lymphocytic infiltration in intestines; myocardial anomalies in heart tissues; and neuronal necrosis with vascular congestion in the brain. These histopathological biomarkers are critical for assessing the sub-lethal impacts of pesticide exposure on fish health and can inform environmental monitoring and management strategies. The findings underscore the urgent need for implementing eco-friendly pest control measures to safeguard aquatic biodiversity and ensure the sustainability of aquaculture practices

Pesticide, Labeo rohita, Catla catla, Cirrhinus mrigala, bioindicators, Ecotoxicology

The reviewed studies collectively illustrate the profound histopathological consequences of pesticide exposure on freshwater teleosts, particularly Indian major carps such as Cyprinuscarpio, Labeo rohita, Catla catla, and Cirrhinus mrigala. Exposure to organophosphates, phenols, pyrethroids, and other agrochemicals, even at sub-lethal concentrations, results in severe tissue-level anomalies that compromise physiological functioning and survival. The gills—being the primary site for respiration and osmoregulation—exhibit consistent pathological features such as epithelial hyperplasia, lamellar fusion, aneurysms, desquamation, and necrosis. These changes impair gaseous exchange and disrupt ion regulation, rendering the fish vulnerable to hypoxic stress and secondary infections. Hepatic tissues, critical for detoxification and metabolism, show marked vacuolation, sinusoidal dilation, cellular degeneration, and necrosis—reflecting systemic toxicity and compromised metabolic function. The kidney, an essential organ for excretion and osmoregulation, also shows degenerative changes such as tubular atrophy, glomerular damage, and interstitial hemorrhage, which can ultimately impair renal function and fluid balance. These findings underscore the bio-indicator potential of histopathological endpoints in aquatic toxicology. They also highlight the urgency of re-evaluating pesticide use near aquatic ecosystems, advocating for eco-friendly pest control alternatives and stricter regulations on agrochemical discharge. Persistent sub-lethal exposure not only threatens fish health and biodiversity but also risks collapsing aquaculture productivity and aquatic food chains, thereby impacting socio-economic structures dependent on freshwater resources

Srianga Tilak Patnaik and Sonali Ghosal (2021). Pesticide Pollution and its Histopathological Effects on Carps: An Overview. Biological Forum – An International Journal, 13(2): 754-758.