First report of Gussevia asota (Monogenea: Dactylogyridae), destructive parasite of A stronotus ocellatus (Perciformes: Cichlidae) in Europe

During epizootological monitoring of local pet-shops and aquarium fish breeders, 45 juvenile fish of Astronotus ocellatus Agassiz, 1831 were examined in March 2013 and October 2014. Fish were imported from a Singapore farm. We found massive infection by Gussevia asota Kritsky, Thatcher & Boeger, 1989 with 100% prevalence and high mean intensities 246 and 265 parasites. Fish displayed visible asphyxia, neurological symptoms, uncoordinated locomotion and sudden death. High 98% mortality of imported juveniles suggests reduced capacity to tolerate hypoxia among oscar juveniles. This is the first report of infection by G. asota in A. ocellatus juveniles in commercial shop from Slovak Republic, in Europe.