Ông Kỳ is a Vietnamese producer of traditional fish sauce from Phú Quốc Island. The brand is associated with Thành Thiên Lộc Company and has been present in northern Vietnam since at least 2014 while its official nationwide launch took place in 2016. Production is based in Dương Đông on Phú Quốc Island. Carefully selected fresh anchovies caught in the waters surrounding the island are used as the principal raw material. These include black, red and striped anchovies harvested during the appropriate fishing season. The fish are combined with sea salt sourced from the coastal region of Bà Rịa–Vũng Tàu. The mixture undergoes natural fermentation for approximately 12 months in large traditional wooden barrels. The producer monitors the microbiological and chemical properties of individual batches in its own laboratory. The sauce is made without added sugar, water, preservatives, artificial colors or flavor enhancers. The finished product has a clear amber color with reddish highlights, a pronounced aroma of fermented anchovies and a complex savory-salty flavor. The range includes fish sauces with natural nitrogen levels from approximately 35N to 43N. Its highest-quality varieties belong to the nước mắm nhĩ category which refers to sauce obtained from the first extraction of the fermented fish mixture. Ông Kỳ products carry the protected Phú Quốc geographical indication which confirms their origin and production according to the prescribed traditional method on the island.