eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2018-12-25 15 4 881 886 10.13005/bbra/2698 32714 article Areej O. Bakhraibah 1 Department of Biology, Faculty of Science, University of Jeddah, Saudi Arabia. The type of hosts that parasites choose is an interesting topic of study. The harmful diseases that infect marine animals are mostly known to be parasitic, such as monogeneans, Copepods and Isopods infections. The primary purpose of this study was to determine the parasitic infections of shark (Carcharhinus melanopterus) and of Scarus fish in the Red Sea located in Jeddah City of Saudi Arabia. For this purpose, 33 Carcharhinus melanopterus and 30 Scarus fish were examined for ectoparasites using wet mount under a light microscope. Collected parasites were identified as, monogenea (Dactylogyrus sp and Erpocotyle tiburonis), Copepoda (Pandarus sinuatus, Anchistrotos tangi and Hatschekia sp) and Isopoda (praniza larva of Gnathia sp). The second purpose of this study was to compare the percentage between Scarus (Osteichthyes) and shark fish (Chondrichthyes) in terms of parasitic infection. Our findings revealed that Monogenea and Copepod infections were found on gills of sharks while Scarus fish were infected by Copepod and Isopod parasites. Parasitic infections can be caused by a number of factors ; it might include the biological and ecological characteristics of the parasite and the host it infests. https://www.biotech-asia.org/vol15no4/a-comparison-study-between-external-parasites-that-infect-scarus-fish-osteichthyes-and-carcharhinus-melanopterus-fish-chondrichthyes-in-red-sea-coast-of-jeddah-saudi-arabia/ Carcharhinus Melanopterus; Comparison; Copepoda; Chondrichthyes; Isopoda; Monogenea; Osteichthyes Red Sea; Saudi Arabia (Jeddah); Scarus Fish