The disease control measures in respect of domestic and wildlife aquatic species in the Republic of South Africa (RSA) are shared between two Directorates in the Department of Agriculture. The Directorate of Animal Health is responsible for disease control measures in respect of Salmonidae, while the Directorate of Plant and Quality Control regulates the introduction of exotic and unwanted aquatic species into the RSA. The activities and interests of commercial aquaculture are coordinated through the South African Aquaculture Organization and a national coordinating committee under the control of the national Department of Agriculture. Four diseases of trout are notifiable under the terms of the Animal Diseases Act (Act 35 of 1984), namely viral haemorrhagic septicaemia, infectious pancreatic necrosis, infectious haematopoietic necrosis and bacterial kidney disease. The zoosanitary measures in respect of these diseases require State intervention after detection of occurrence. Sampling procedures for the diagnosis of diseases, maintenance of the disease-free status of trout farms accredited for export purposes and requirements for the import of ova are based on the standards recommended in the International Aquatic Animal Health Code of the Office International des Epizooties. Zoosanitary control of other aquatic species not related to aquaculture--especially ornamental fish--may be unnecessary. An embargo, through existing legislation on the importation of unwanted species, has been the only means of protecting inland species. The author concludes by evaluating the need for, and the feasibility of, additional legislation for the zoosanitary control of other aquatic species.