Thai Fish Sauce Is a Category, Not a Bottle, and Nam Pla O Is Not Nam Pla Nua
Southeast Asia's best seafood, sold by weight in the morning and cooked in a banana leaf by the afternoon, and a condiment aisle that is more complicated than it needs to be.
I asked for pla thot. The woman looked at me, looked at the tank, and then went and got a fisherman on the phone, in Isan, about the particular fish I had pointed at. The dish I got was better than anything I have eaten on a coast in Europe, and the reason was that the fish had been in the water that morning and the restaurant knew whose boat it came off.
That is what Thai seafood actually is, and it is worth understanding before you order.
Last verified 1 August 2026.
How Thai seafood is sold
By weight, alive, and the price is the day price. You point at a fish and the man weighs it and tells you what it costs, and the number changes with the market that morning rather than with a menu printed last year.
Which means a menu with a price on it is a sign of a restaurant that is not buying good fish, and this is a genuinely useful heuristic for picking a place near a pier.
Ask for the fish you want, and if the kitchen does not have it the right answer is that they will not cook it, not that they will substitute something cheaper and not tell you.
And freshness is a two hour window. In the heat, a fish that was excellent at six in the morning is a liability by two in the afternoon, which is why the morning market is the place and the lunch sitting at eleven is the meal.
The dishes worth knowing before you go
Pla thot, or pla thot pla muk, is fried fish with a sweet, sour and salty sauce thickened with egg. It is the order of the day at a coastal fish restaurant and it is a genuinely good way to learn what a fish tastes like, because the sauce is loud and the fish is not hidden.
Pla thai, or pla thai pla muk, is steamed fish. The least cooked, the simplest and the one to order if you want to taste the fish. Steamed in a banana leaf or on a plate, with ginger, chilli, garlic and a splash of fish sauce, and nothing else.
Goong chao nam pla, or phat kramung, is stir-fried prawns in garlic and pepper, which is the single most consistently good thing on most Thai seafood menus and which half the people ordering seafood abroad do not know exists.
Plapla, or pla jaroen, is a sour soup with a lot of lemongrass and galangal, which is hot in a way that is about sourness rather than chilli heat.
And pla som, fermented fish salad, is a southern thing and a divisive one that you should try once because it is a real taste and it is not a metaphor for anything.
Pla tha, and the banana leaf
Pla tha is fish curry wrapped in a banana leaf parcel and steamed, it is everywhere on the Andaman and Gulf coasts, and it is the single best thing about a longtail day trip.
The parcel is a delivery method and it is a good one: the leaf holds moisture in, the fish stays delicate instead of drying out, and it survives the journey back from an island in a way a plate does not.
You are meant to eat it out of the packet, and the topmost leaf is a layer to lift off rather than a lid to throw away, and everybody in Thailand knows this and nobody mentions it, so you will look slightly foolish the first time and not after.
The sauce is coconut and red curry paste and it is a genuine coconut curry, and it is sweet and rich and very mildly hot, and this is the dish that surprises western visitors who have decided that all curries are fire.
Fish sauce, which is a category
Nam pla, the general word, covers an enormous range of products, and the difference between them is the single most useful thing anybody can teach you about ordering Thai food.
Nam pla o, the first pressing, is the clear, light, delicate one. It is what you want in a salad, in a som tam, and anywhere you want the fish to taste like fish. It is the highest quality and it is more expensive.
Nam pla nua, the second pressing, is darker and far saltier, and it is the everyday workhorse. It is what a plate of stir-fried food is seasoned with and it is what a bowl of soup is salted with.
And there are specialty bottles that are not fish sauce at all in the way you expect, including the squid-based one, the fermented shrimp one, and the sweet dipping sauce in a tiny pot on a noodle stall table that you mix with chilli powder and lime.
The practical consequence is that a restaurant using the good one is cooking better than a restaurant using the cheap one, and the cheapest thing you can do is ask which they use, and the answer is genuinely interesting.
How to buy it to take home
Buy it in a plastic bottle with a proper label from a shop, not in a plastic bag from a market, because the bagged version is decanted and may be older and diluted and you have no idea.
Check the date, which is on the back, and the label is bilingual. A clear pale liquid is usually the good first pressing and a very dark one is a different product.
And put it in checked baggage, wrapped, in a sealed bag, because a bottle of fish sauce in hand luggage is a liquids problem and a smell problem on the other side.
And know the export rules before you buy, because food products leaving Thailand are a controlled category rather than an unlimited personal allowance, and it is a much more common question at departure than people expect.
What people get wrong
They order pla thot and assume the sauce is the point. It is not. It is a delivery mechanism for a fish that was alive this morning, and the reason to order it is the fish.
They assume seafood is expensive on the coast. It is generally cheaper than almost anywhere comparable, and a whole grilled fish for a couple of people is one of the best value meals available in Thailand.
And they skip the morning market, which is where the actual skill is. The restaurant is applying somebody else's skill. The market is the thing worth an alarm.
