Fish sauce is a condiment made from fermented fish and salt.  It is added to dishes during the cooking process as well as being used as a base in dipping sauces. Fish sauce and its derivatives impart an umami flavor to food due to its glutamate content. It may be prepared from different species of fish and shellfish, and from using the whole fish, or by using just fish blood or viscera.
Most fish sauces contain only fish and salt, but some add a variety of herbs and spices.