Gilbert, Beric M: Seasonal occurrence and microhabitat specificity of Paradiplozoon ichthyoxanthon Avenant-Oldewage in Avenant-Oldewage et al., 2014 (Monogenea: Diplozoidae) infecting Labeobarbus aeneus (Burchell) (Teleostei: Cyprinidae) from the Vaal Dam, South Africa: water quality and host size as determining factors