This study concentrated on the distribution of fish species infested by isopods during dredging operations in Manzala Lake. Samples were collected by using different fishing gears and methods from different sites of the lake during the period from 2019 to 2021. Species infested by isopods were identified and recorded. Most of the infestations were found in the western and El- Boughaz (Northeastern) regions. Livoneca redmanii (Isopoda, Cymothoidae) was observed in all seasons infesting fish of great economic importance. The most infested fish species by L.redmanii in Lake Manzala during the period of study were D. labrax and D. punctate, followed by C. ramada, while C. zillii was the least. Infestation of gills in different fish species by L. redmanii was detected on one or both sides of the gills. Sometimes two L. redmanii were noticed, one of which was recorded on one side and the other on the other side. In addition, different stages of growth of L. redmanii were observed in D. labrax. We suggest biological control by scientific researcher specialists to prevent the further spread of this parasite and protect the fisheries development in the lake.