A survey on monogeneans parasites infestation of goldfish emphasizing the farming carp species

Goldfish (Carassius auratus), a carp fish of Cyprinidae family, is one of the most popular aquarium fishes in Iran and also in the world. Ornamental fish trade, especially Goldfish, is aged over a hundred years. If we believe that any aquatic species or country has its own specific and unknown fauna of pathogens, the risks of transmission of these pathogens by importing ornamental fishes (whether at national, provincial or municipal level) will become more obvious. However, few researches have been done about parasitic infections in ornamental fishes. Identification and investigation of fish pathogens, especially parasites, prior to transportation to new place is considerably important in the preventing and restricting the transmission of these pathogens. In this study, skin and gills of 100 goldfish were examined by wet mount in order to investigate monogenean parasites. Nine species of parasites from 3 families (Dactylogyridae, Gyrodactylidae and Ancylodiscoididae) were isolated and identified in fishes, including 4 species of Gyrodactylus (Gyrodactylus kobayashii, Gyrodactylus Gurleyi, Gyrodactylus longoacuminatus and Gyrodactylus sp.), 4 species of Dactylogyrus (Dactylogyrus vastator, Dactylogyrus formosus, Dactylogyrus baeri and Dactylogyrus sp.) and 1 species of Ancylodiscoides. Gyrodactylus kobayashii (10%) were the most common parasites found, followed by Dactylogyrus vastator (9%). Although these fishes are quite resistant against such pathogens, transporting them to a new aquatic ecosystem could transfer these parasites and cause infestation of healthy fishes, which brings about financial losses and casualties.