The Crustaceans used for commercial sale are crabs, shrimps and lobsters. All these animals are subjected to the invasion of the marine parasites such as copepods, branchiura, anchor worms, fish lice, and gnathia. These parasites affects the body of the crustaceans and cause diseases and ultimate death. This will lead to decrease in number of commercial quantity of crustaceans and fisheries. Hence, will be responsible for high economic loss.