Abstract
This research was carried out in order to get overview of current status of infestation with Dactylogyrus spp. and other parasites in common carp (Cyprinus carpio) collected from the ponds around Mashhad in northeast of Iran. A total of 100 common carps from March to December 2011, 61 (61 %) specimens were hosts to parasites. Monogenea dominated the parasite load most of all fishes, whereas Argulus foliaceus (Arthropoda) was the less parasite. Parasites were found as followed: Dactylogyrus extensus (29 %), Dactylogyrus anchoratus (2 %), Ichthyophthirius multifiliis (10 %), Trichodina nigra (7 %), Capillaria spp. (5 %), Procaecum spp. (2 %), Argulus foliaceus (2 %), and Lernaea cyprinacea (4 %). Seasonal changes in the abundance of parasites were evident for most taxa in which the prevalence of parasitic infection and diversity were more in summer than other seasons. The result of this study provide a better aquaculture conditions and help to solve some of the problems of fish farmers.