Popular throughout Southeast Asia, fish sauce can be any of various mixtures based on the liquid from salted, fermented fish. This extremely pungent, strong-flavored and salty liquid can range in color from ochre to deep brown. It's used as a condiment and flavoring, much as soy sauce would be used. Fish sauces may be flavored variously such as with chiles or sugar depending on the use. Asian markets carry a wide variety of these pungent sauces including nam pla (Thai), (Vietnamese), patis (Philippines) and shottsuru (Japanese). Fish sauce is also referred to as fish gravy.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.