Argulusis is invasion disease of fishes caused by gill-caudal ostrocods of the orderly argulus parasitizing on carp species, salmonides, sedge fishes and other species. The document consists of 5 Secs. Section 1 lays down general provisions. Section 2 regards epizootology. Section 3 regards diagnosis. Section 4 clinical symptoms and patologo-anatomical changes. Section 5 regards prophylaxis and arrangements for combating the afore-mentioned disease.