Made from fish or krill (tiny crustaceans) that are coated in salt and fermented for up to two years, fish sauce is a staple condiment used in a lot of East or South-East Asian cooking.
Its rich, umami flavor makes it perfect for seasoning meals such as pad thai, pho, or stir-fries.
It’s exactly the kind of sauce you might use for one or two recipes every now and then before putting it away and forgetting about it. If this is you, you’re probably wondering what the shelf life of fish sauce is and whether it goes bad.
How Long Does Fish Sauce Last?

You’ll be pleased to hear that fish sauce lasts for a very long time. Even after the best-by date, it can last months or, sometimes, even years past the date due to its high sodium content.
But bear in mind the longer it is left alone, the more the quality will degrade. You might find that after years of not using it, the flavor has turned mild or is entirely lacking.
The good news is fish sauce rarely becomes unsafe to eat, but even so, without its trademark umami flavor, it won’t add much to your meal.
If this is the case, you might want to purchase a new bottle, although this is down to personal taste and whether you prefer something milder.
In terms of time periods, you can expect an unopened bottle to stay in good quality for the duration of the best-by date plus a year. It gets better—it can last between three and four years after bottling, although, again, watch out for degradation in taste.
An opened bottle, stored in your pantry, can stay tasty for between three and six months or over twelve months if kept in the fridge. For tips on how to store your fish sauce, simply keep reading!
How Do I Store Fish Sauce?

The best part about storing fish sauce is it’s incredibly easy! An unopened bottle will be fine for a long time if kept at room temperature in a cool, dark place, such as a pantry or cupboard, away from a heat source. A cupboard or shelf dedicated to sauces is perfect.
If opened, remember to seal the lid tightly after use. The bottle can be left in your pantry or cupboard, but for prolonging taste quality and freshness, it is recommended you leave it in the fridge.
How Do I Know If Fish Sauce Has Gone Bad?

As mentioned, the likelihood of fish sauce going bad is rare. If the worst happens and it does go off, you’ll see mold or yeast growing on the sauce surface or clinging around the neck of the bottle. This is a sure sign it’s time to throw out the fish sauce.
Good fish sauce is a dark reddish-brown color. If there is discoloration, this is another indication it has gone off and should be discarded. Also, you can tell if fish sauce is bad by using your nose. If it’s fine, it will smell of (no prizes for guessing) savory fish. If bad, it will emit a rotten odor, signaling it is not safe to eat.
There are some circumstances in which you might think your fish sauce has gone bad, but it is actually okay. If you spot these in your fish sauce, you need not worry:
- Clear crystals on the bottom—this is sea salt, and its formation is a natural process that won’t affect the taste.
- Small particles floating about—this is protein. When the fish sauce is exposed to a change in temperature, protein precipitation occurs. Protein precipitation, just like sea salt crystal formation, is a natural process. Sauce safety and taste won’t be affected.
Are There Any Substitutes For Fish Sauce?

Picture this: you’ve just begun preparing a pad thai dish and have realized you’re out of fish sauce, or it’s lost its strong flavor.
Or perhaps you still have fish sauce lying around but have recently switched to being vegan or vegetarian. Fish sauce is, of course, for those who include fish in their diet, but you are now searching for alternatives.
You’re in luck! Below is a short list of sauces that can be used in place of fish sauce if need be:
- Soy sauce: With a slightly different taste but still having an umami flavor, soy sauce can be a useful vegetarian/vegan alternative. For extra freshness, mix it with rice vinegar using a 1:1 ratio.
- Tamari: Similar to soy sauce but with far less wheat, this is perfect for those who cannot eat gluten.
- Oyster sauce: This is not vegan or vegetarian but is sweeter and thicker than fish sauce. Do remember, however, that some dishes require the thin consistency that fish sauce has.
- Vegan fish sauce: Made of soy sauce, liquid aminos, and shiitake mushrooms.
What’s The Bottom Line?
Because of the unlikelihood of it going bad, fish sauce is essential for adding great flavor to healthy meals and is easy to keep fresh and of good quality. There are alternatives to fish sauce, but do make sure good fish sauce is passed on to someone who will use it if it’s no longer for you!