A scientific seminar entitled "A review on the species diversity of dactylogyrus monogeneans, life cycle and pathogenesis" was held in the meeting room by Mr. Mehrdad Asghar Nia, the expert of the National Inland Water Aquaculture Institute. Since the species of the genus dactylogyrus have a direct life cycle and do not require host, they quickly multiply and given their high hosting capability, they can quickly infect a large number of fishes in the short term. Some species of this genus, life cycle, general characteristics, nutrition, biology, signs and symptoms of infection, physiology, hosting feature, abundance and pathogenicity of the parasite were discussed at the seminar. Finally, it was suggested that the uncontrolled entry of fish into the country be strictly prohibited.