Dissostichus is genus of fish found in southern oceans. Individuals may live for over fifty years, reaching lengths over two metres and weigh over 200 kilograms.
The genus contains two species. Dissostichus eleginoides, the Patagonian toothfish, is the type for the genus and is found in temperate and sub-antarctic waters and Dissostichus mawsoni, the Antarctic cod or toothfish, which occurs in icy waters near Antarctica.