fish sauce
A salty, pungent liquid made from fermented, salted fish, typically anchovies -- a foundational seasoning in Southeast Asian cooking that adds deep savory umami the way soy sauce does elsewhere. It smells sharply fishy straight from the bottle but should melt into a dish's overall flavor rather than taste distinctly fishy once cooked in.
Buying guidance
Read the ingredient list -- quality varies enormously by brand; the best versions list only fish and salt, while cheaper ones dilute with water and sugar. Add it a small splash at a time and taste, since salt concentration varies widely between brands and a tablespoon of one brand can be far saltier than another's.
Substitutions
- Soy sauce or tamari -- replaces the salt and some umami but lacks fish sauce's fermented depth; good for a vegetarian or vegan version.
- Worcestershire sauce, in a smaller amount -- contains anchovy, so it's a reasonable stand-in when fish sauce specifically is unavailable but anchovy is acceptable.
- Soy sauce plus a small amount of miso paste -- adds back some of the missing fermented complexity.
Tips & common mistakes
A little goes further than the smell suggests -- the sharp, fishy aroma straight from the bottle is much stronger than how it tastes once cooked into a dish, so measure rather than pouring by nose, or a dish can end up both saltier and fishier than intended.
Storage
It's essentially a salt brine and doesn't spoil the way fresh food does -- most bottles keep well at room temperature even after opening, away from direct sun, though refrigeration can slow gradual flavor changes if it's used slowly. Some sediment or small white crystals settling at the bottom of an older bottle is usually just salt or protein, not spoilage; give it a shake.