This study was conducted on 525marine fishes represented as 175 of each seabass Dicentrarcus labrax,Mullet sp (Mugil cephalus and Moolgarda seheli). The clinical examination of the infested fishes  showedrespiratory distress, surface swimming, bulging of opercula, sluggish movement, emaciation , severe erosion and hemorrhages of gills .Hemorrhagic areas were found on gill cover and in late stages,as well as  external ulcers located in the gill filaments. Caligus and Lernanthropus species were isolated and identified from all the examined fish species. The total prevalence of the examined fish species was 55.05% .The prevalence of crustaceans in D.labrax ,M.cephalus and M.seheli were 48.57, 78.28 and 38.29% respectively.The infested fishes with such crustaceans led to loss of body weight consequently, high economic losses at marketing in marine farms.                                                            
This problem was recorded and discussed.