Fish sauce and oyster sauce are two essential Asian condiments that are often confused but serve very different purposes. Fish sauce is a thin, amber-coloured liquid made from fermented fish - it adds salty umami depth to dishes. Oyster sauce is a thick, dark brown glaze made from oyster extract - it adds sweet-savoury richness and shine. Most Asian kitchens keep both on hand.
What Is Fish Sauce?
Fish sauce (called nuoc mam in Vietnamese, nam pla in Thai, and patis in Filipino) is made by fermenting small fish (usually anchovies) with salt for 12 to 18 months. The result is a thin, translucent amber liquid with an intensely salty, funky, umami-rich flavour. It smells strong on its own but transforms dishes when cooked.
Key characteristics:
- Thin, watery liquid
- Amber/brown colour
- Very salty and pungent
- Strong fermented aroma
- Used in small amounts (teaspoons)
- Essential in Thai, Vietnamese, and Filipino cooking
What Is Oyster Sauce?
Oyster sauce is made from oyster extract, sugar, salt, and thickeners. It has a thick, glossy consistency and a sweet-savoury flavour with caramel undertones. Unlike fish sauce, it has a mild aroma and is used more generously in cooking.
Key characteristics:
- Thick, syrupy consistency
- Dark brown, glossy
- Sweet-savoury, mild
- Pleasant, mild aroma
- Used in tablespoons
- Essential in Chinese and Thai stir-fries
Fish Sauce vs Oyster Sauce - Quick Comparison
| Fish Sauce | Oyster Sauce | |
|---|---|---|
| Made from | Fermented anchovies + salt | Oyster extract + sugar + soy |
| Texture | Thin liquid | Thick glaze |
| Flavour | Salty, funky, umami | Sweet-savoury, caramel |
| Aroma | Strong, pungent | Mild, pleasant |
| Colour added | Almost none | Dark brown glaze |
| Main cuisines | Thai, Vietnamese, Filipino | Chinese, Thai |
| Substitutable? | No - they serve completely different purposes | |
When to Use Fish Sauce
- Pad thai - the key seasoning (not soy sauce)
- Vietnamese pho - added at the table for salt and depth
- Thai curries - balances coconut milk sweetness
- Dipping sauces - nuoc cham (fish sauce, lime, chilli, sugar)
- Som tum (green papaya salad) - essential for the dressing
- Marinades - tenderises meat while adding umami
- Any dish needing salt + umami - use instead of plain salt
When to Use Oyster Sauce
- Chinese stir-fries - the classic stir-fry sauce base
- Stir-fried vegetables - broccoli, kai lan, bok choy with oyster sauce
- Fried rice - adds colour and savoury sweetness
- Noodle dishes - lo mein, chow mein
- Glazes - brush on grilled meat for shine
- Thai pad see ew - one of the main sauces
Can You Use Them Together?
Yes - many recipes use both. A classic Chinese stir-fry sauce might combine light soy sauce, oyster sauce, and a splash of fish sauce for maximum umami. Thai cooking frequently uses fish sauce and oyster sauce in the same dish. They complement rather than compete with each other.
Vegetarian Alternatives
For fish sauce, look for mushroom-based "vegetarian fish sauce" or use light soy sauce with a squeeze of lime. For oyster sauce, vegetarian oyster sauce (made from mushroom extract) is widely available and works as a direct substitute in any recipe.
Popular Brands in Australia
Fish Sauce
- Megachef - premium Thai fish sauce, clean flavour
- Three Crabs - Vietnamese classic, slightly sweeter
- Squid Brand - Thai staple, widely used
- Red Boat - artisan Vietnamese, single-ingredient
Oyster Sauce
- Lee Kum Kee Premium - the gold standard
- Lee Kum Kee Panda Brand - great everyday option
- Megachef - Thai premium oyster sauce
Where to Buy in Australia
Asian Pantry stocks all the major fish sauce and oyster sauce brands, delivered Australia-wide. Browse our sauces collection to find the right ones for your kitchen.