The current investigation was undertaken toArgulus sp. infestationintensity in Indian major carps collected from different ponds of Darbhanga district, Bihar, India. A total of 4080 specimens were examined for ectoparasite, Argulus sp. infestation out of which 572 specimens found to be infected. The observation revealed specieswisethat maximum prevalence of the Argulus was recorded in L. rohita (25.88%), C. mrigala (20.29%)andC. catla (13.23%) post monsoon season. The minimum prevalence of the Argulus was recorded in L. rohita (12.64%), C. mrigala (9.70%) and C. catla (3.52%) in the winter season. The prevalence (14.01%), abundance (2.22) and mean intensity (15.86) of parasitic infestation was recorded in a year. The bigger size specimen exhibited more parasites from the hosts.During monsoon and post monsoon seasons showed high prevalence of Argulussp. infestation. So, fish health management should be in practice in hatchery and stocking ponds.