The host specificity of monogeneans in inland waters of China was studied.The great specificity and the obvious difference of specificity among four major families of monogeneans were observed.According to published records,more than 60% species of monogeneans were found only on 1 host species,and about 75% species on 1 host genus,over 97% species on 1 host family.No monogenean species is able to parasitize on hosts over 3 families,however,the host tree of the monogenean species Dactylogyrus magnihamatus...