Study of Argulus spp. infestation rate in Goldfish, Carassius auratus (Linnaeus, 1758) in Iran

Members of the genus Argulus, or fish lice, are common parasites of fresh water fish. The present study aimed to investigate necessarily the rate of infestation by argulids and determine the infesting species in goldfish in order to control the invasion of parasite in native and cultured fish population. For the present study, 1200 live goldfish were collected randomly from 10 ornamental fish farms from different areas of Iran in summer 2010 and were investigated macroscopically and microscopically. The number of parasites in every infested fish was numerated and identified by the morphologic key characteristics under light microscope as alive and as fixed in 70% ethyl alcohol. The results showed that 19.17% of sampled goldfish were infested with Argulus coregoni (Thorell, 1864),Argulus japonicus (Thiele, 1900), and Argulus foliaceus (Linnaeus, 1758). The most frequent infestation was with A. japonicas (12.5 %), the least frequent was with A. coregoni (1.6%), and the frequency of A. foliaceus infestation was 5%. Moreover, in this study, multi-cellular and unicellular parasites such as Gyrodactylus spp, Dactylogyrus spp, Trichodina spp and Ichthyophthirius multifiliis (Fouquet, 1876), were observed in infested fish.