The genus Lernaea (Anchor worm), a parasitic copepod is found to parasitize in the brood stock, nursery, and grow out carp culture system. Lernaea species infestations were also found infecting Indian and Chinese major carps. After the larval nauplius and copepodites juvenile stages, males and unfertilized females of lernaeaid copepods have typical cyclopoid features. The fertilized female undergoes transformation, and becomes an attached worm-like parasite which are visible to the naked eye which attach themselves under the scales of cultured carps. Several species of anchor worms adversely reduce the fish energy and increase the chances of secondary infections. Even in ornamental aquaculture industry that has grown into an important sub-sector within the fisheries segment, incidence of Lernaea diseases which crop up during culture badly affects the profitability of the ventures.
Under high stocking density, the risk of stress increase and a significant proportion of the stock may become infected. Lernaeaid parasite burden of Catla catla was studied, fouling was observed on surface during an outbreak of the infection in an aquaculture grown out pond where in polyculture of freshwater fish is carried out. An attempt was made in the present case studies to document the infection, mortality rate parasite burden occurred in the grown out pond in detail.