Vietnamese fish sauce, nước mắm is very much like its Thai cousin and the same advice applies. Simple ingredients. Anchovies (cá cơm), salt (muối), water (nước) at most, although the best only contains the first two.   First-pressing sauce (mắm nhĩ ) is best and if you want a stronger flavour look for mắm nêm or mắm ruốc.   Phú Quốc island off the southwest coast of mainland Vietnam near the Mekong Delta and Ho Chi Minh City (Saigon), is considered to make the best quality sa