For any who wonder, "fish sauce" has pretty much been a universal condiment in much of the world for thousands of years. There are lots of variations, but all pretty similar. The Romans called it "garum" and relied heavily on it for seasoning many of their dishes.
While I was stationed in Vietnam (back in Pre-Cambrian times), there was a nuoc mam factory nearby, and when the wind was right we had a hard time dealing with the aroma. Very tasty stuff when properly used though. I always have a bottle in my pantry. I believe in Thailand it's called nam pla.
Basically, it's just fish and salt, allowed to ferment and age, then strained.
While I was stationed in Vietnam (back in Pre-Cambrian times), there was a nuoc mam factory nearby, and when the wind was right we had a hard time dealing with the aroma. Very tasty stuff when properly used though. I always have a bottle in my pantry. I believe in Thailand it's called nam pla.
Basically, it's just fish and salt, allowed to ferment and age, then strained.
In the early 20th century, the celebrated Institut Pasteur in Paris studied nuoc mam for 16 years, from 1914 to 1930, to understand the fermentation process that Vietnamese peasants had been employing for centuries. The two necessary ingredients were fish and salt. The fish were usually small ones of the Clupeidae family, to which herrings and sardines belong. The fish sat in salt for three days, which produced a juice, some of which was reserved to ripen in the sun, while the remainder was pressed with the fish to produce a mush. The two were then mixed together and left for three months, sometimes much longer. Then the solid parts were strained out.
-- from Salt, A World History, by Mark Kurlansky