Fish are well known to act as direct or indirect carriers of different zoonotic pathogens including parasites, viruses, bacteria and fungi. Parasitic infection is one of the most important problems facing fish breeding and production at commercial scales. So the most important reason for studying fish parasites is to study the relationships of these parasites to fishes, animals and man and also to understand some human health problems. Helminthosis is the disease caused by the presence of helminth parasites within or outside the gastrointestinal tract of an individual. All species of animals can be infected with helminth parasites. The infection usually is more severe in the very young and the very old or immunocompromised individuals. Some adult animals can thrive fairly well while infected with some helminth parasites without showing obvious clinical signs while the vast majority suffer reduced productivity under heavy worm burdens. It appears that some breeds of animals are more resistant to certain helminth parasites than others. Helminthosis has been a long time standing problem against breeding of fish hosts leading to economic loses that may reach billions of dollars.