During the present study, 120 fishes (Catla catla) maintained at a fish hatchery in Muzafargarh, Pakistan were examined for lernaeid parasites over a 12 months period from February 2000 to January 2001. Out of 120 C. catla fishes, 96 were infested, showing an overall prevalence of 80%. Six species of Lernaea recovered were: L. cyprinacea, L. polymorpha, L. ctenopharyngodonis, L. arcuata, L. lophiara and L. oryzophila. L. cyprinacea showed the highest parasitic burden (3.61 parasites per fish), while L. lophiara had the lowest parasitic burden (1.00 parasite per fish). The infestation was lowest in fishes with body length of 23.00-25.75 cm and maximum in 25.76-31.25 cm long fishes. Similarly, the parasitic infestation increased with body weight range of 160-258 gm to 456-553 gm, while almost no parasites were seen in heavier fishes (>553 gm)
