An isopod parasite of family Aegidea was collected from marine fish, Sardinella gibbosa (new hosts) over 2-years period from 2007 to 2008. The fish hosts were captured in the coastal waters of Port Said, Egypt. The Cymothoa sp. & Aega sp. were only collected from skin of the new host, Sardinella gibbosa, and described on the basis of female specimens. The morphological characteristics of were discussed in details. Comparing the present specimens with the previously reported Aega sp. showed that the present material belongs to the type species of the genus: Aega psora (Linnaeus, 1758). Monthly and seasonal patterns in infestation rates [N=593, W +/- SD (range) =50.09 +/- 3.8 g]. Parasitic specificity and prevalence are given Mean prevalence, P = 24 +/- 5.5 and mean intensity, MI +/- SD =28.44 +/- 16.19 and total number of infestation were estimated 59 (10.35).