This is a clear, thin brown sauce made from small fish and salt left to ferment for many months. The pungent and complexly flavoured liquid is then decanted and bottled. The quality of fish sauces varies tremendously. It is widely available in supermarkets and Asian stores. Buy the best quality possible, preferably naturally fermented and without additives. Lao use locally bottled Thai (nam pla), Chinese and Vietnamese fish sauces.