Study of ectoparasite contamination of rainbow trout Oncorhynchus mykiss (Walbaum, 1792) in Aquatic Animal Health Research Center's farm, Faculty of Veterinary, University of Tehran

This study was conducted on 270 individuals of rainbow trout kept in the research farm of Aquatic Animal Health research Center, Veterinary Hospital in Karaj, Mardabad from January 2012 until the end of March 2013. The fish have been chosen from three sources, provinces of Chahar Mahal Bakhtiari, Markazi and Mazandaran. In this study, the highest and lowest infection prevalence was related to Ichthyophthiriusmultifiliis and Chilodonella sp., respectively.Chi-square analysis was used for statistical analysis. A total of 166 samples out of 270 samples (61.5%) showed the infection by ectoparasites including: Ichthyophthiriusmultifiliis with 99 pieces (36.7%), Trichodina sp. with 18 pieces (6.7%), Chilodonella sp. with 7 piece (2.6%), Gyrodactylus sp. with 20 pieces (7.4%) and Lernaea sp. with 22 piece (8.1%).