Abstract
Ergasilids are copepods living in the river mouth of freshwaters and parasitic on Teleost fish family in both natural and artificial environments. So far, 5 species of the copepod have been discovered that belong to the genus Neoergasilus. This copepod is most likely to be disseminated through aquarium trades, aquaculture and over-nutrition, or construction of sand carrying water. The females of Ergasilidae are external parasites attaching to the anal and dorsal fins and sometimes to gills and nasal cavities of fish living in freshwaters. In total, 552 pieces of ornamental fish (301 males and 251 females) with length of 5-10 cm from fish (Poecilia sphenops) species (Singapore, Sandy, Dirigible and scorpion's tail) were collected from ornamental fish stores in different regions of Kerman, Iran during 1 year in 2012-2013 and tested in order to examine Neoergasilus japonicus infestation. From 188 adult females Neoergasilus japonicus specimens recorded on the fish host, 8 (4.26 %) were on the anal, 120 (63.83 %) on the dorsal, 10 (5.32 %), on the pectoral, 45 (23.94 %) on the pelvic, and 5 (2.66 %) on the caudal fins. In this study, the prevalence of parasitic copepod infestation from Dec. to May was 26.31, 27.69, 26.19, 14, 18.75, and 7.5 %, respectively. There was no significant difference between infestation prevalence in indigenous and non-native fishes (P = 0.18). There were significant differences between different months of year in the prevalence and intensity of Neoergasilus japonicas (P < 0.05). There was significant difference between frequency distribution of Neoergasilus Japonicus infestation in different organs (P < 0.05). The male fish infestation (16.3 %) was significantly higher than female fish infestation (5.6 %) (P < 0.05). Considering that the Neoergasilus japonicus was first observed in native and nonnative ornamental fish in Kerman, further studies should be conducted on the copepod infestation in stores supplying ornamental fish in other parts of Iran to make more accurate judgments.