Abstract
Cymothoid isopods are parasites that cause severe damage to the fish species. The present study was focused to carry out the parasitic infestation on the one of the important marine fish Strongylura leiura during the 2 years period between June 2009 and May 2011. 272 fish specimens collected and about 157 (57.72 %) fishes were infested by the cymothoid which were concealed under the gill arches of the host. Infested parasite was identified as Mothocya renardi. The prevalence rate of parasites during different seasons of the range of host specificity of isopods was studied. Variation of infestation rate also depends on the size, length and weight of the host. The sites of infestation by the parasitic crustaceans are highly specific. The infestation had affected the normal growth of the host fish and also probably leads the high levels of secondary infections.