Comparison of Diagnostic Methods for the Detection of Parasites in Fish

In recent years, Aquaculture has developed very rapidly. However, fish parasitic diseases in fry and fingerling occur often. There are many methods which were used to diagnose fish parasites. In this paper, fifty wild fish belonging to three fish species: roach (Rutilus rutilus), perch (Perca fluviatilis) and bream (Blicca bjoerkna) were collected from Arreso Lake in Copenhagen, Denmark in 2005 to diagnose parasites. Parasitological investigation was implemented by normal observation, compression, digestion and PCR methods at the Fish Disease Laboratory, Pathology Department, Life Science University, Copenhagen, Denmark. The results show a high prevalence of eye fluke metacercaria in wild fish (100% of Blicca bjoerkna infected by Diplostomum  sp.). Each method has advantages and disadvantages. The classical methods are simple, cheap and easy to apply in every fish laboratory. PCR methods produced results rapidly, sensitively and exactly. But this method costs much for equipment, and 

chemicals and needs exacting technique.