Parasitic infestation is a cosmopolitan phenomenon in almost all the habitats, especially among the aquatic biota. Egypt derives its fish production from two resources; natural (marine and inland waters) and aquaculture. In recent years a serious decline in fish production from natural resources was recorded and a number of challenges were identified from which overfishing, illegal fishing techniques, pollution, habitat degradation…etc.  Five years ago, a new challenge appears on the surface and affected dramatically the fish production and quality in some fishery resources in Egypt, the isopod parasites. Although isopod parasites were observed in marine fisheries for a long time and considered as a part of the aquatic ecosystem, today it received considerable attention because they cause serious damage to our fishery resources especially in one of the largest inland lakes in Egypt, lake Qarun. Isopods associate with many species of commercially important fishes in the lake causing significant economic losses in commercial fish species ending by loss more than 70% of the lake catch. This study will throw the light on the isopod parasites in lake Qarun with their impacts on the fishery resources as well as propose some practical solutions to overcome this serious problem in Egypt.