South Asia

Masor Tenga: Assam's Sour Tomato Fish Curry

Name: Masor Tenga: Assam's Sour Tomato Fish Curry
Prep time: 20 min
Cook time: 30 min
Total time: 50 min
Yield: 4 servings
Cuisine: Indian (Assamese)
Ingredients: 8 pieces (about 600 g) White fish fillets; 1/2 tsp Salt; 1/2 tsp Turmeric; 3 tbsp Mustard oil (for searing); 2 Potatoes; 2 tbsp Mustard oil (for the broth); 1/4 tsp Fenugreek seeds; 1/4 tsp Mustard seeds; 1/4 tsp Nigella seeds; 2 Dried red chilies; 2 Green chilies; 4 (about 600 g) Tomatoes; 1 tsp Salt; 1/2 tsp Turmeric; 1 tsp Kashmiri chili powder; 400 ml Water; 2 tbsp Cilantro; 2 tsp Lemon juice

A recipe for masor tenga, the home-style fish dish of Assam in northeast India, made with white fish fillets, tomato, mustard oil, fenugreek, mustard seeds, nigella and lemon juice. It covers Assam's food culture of naming sourness tenga, searing the fish first so it doesn't fall apart, and telling the sound and color of tempering.

Published: October 24, 2026Total: 50 minLevel: Beginner

Cooking flow

Cooking steps

STEP 11 / 6

Coat the fish with salt and turmeric

Coating white fish fillets with salt and turmeric until they turn yellow — Coat both sides, leave 5–10 minutes, and wipe off the moisture that comes out

Wipe the fish fillets thoroughly dry with paper towels and coat both sides evenly with 1/2 tsp salt and 1/2 tsp turmeric. Leave for 5–10 minutes, until the surface is lightly yellow and the seasoning has settled in moistly, then wipe off the moisture that has come out once more.

STEP 22 / 6

Sear the fish in mustard oil

Searing yellow white fish fillets in mustard oil in a frying pan to a pale golden color — Leave undisturbed for 2–3 minutes and flip when pale golden

Put 3 tbsp mustard oil in a deep frying pan over medium-high heat and heat for 1–2 minutes until a faint smoke rises. Arrange the fish and, without moving it, sear 2–3 minutes; when a pale golden color has formed, flip and cook about 2 minutes more. It doesn't need to be cooked all the way through. If the surface has set, the fish is less likely to fall apart when simmered. Take it out onto a tray.

STEP 33 / 6

Sear the potatoes

Searing potato wedges to a golden color in the pan used for the fish — Medium heat for 5–6 minutes, until pale gold all over

In the oil left in the same pan, sear the 8 potato wedges over medium heat for 5–6 minutes. Roll them from time to time, and take them out when they are a pale gold all over and a bamboo skewer goes in about halfway. They finish cooking in the broth.

STEP 44 / 6

Temper the seeds and chilies

Popping fenugreek, mustard seeds, nigella seeds and dried red chilies in hot mustard oil in a frying pan — Until the mustard seeds pop and the fenugreek turns a deep brown

Lightly wipe out the oil from the pan with a paper towel, add 2 tbsp mustard oil and heat over medium heat. Add the fenugreek seeds, mustard seeds, nigella seeds and dried red chilies and heat for 20–30 seconds, until the mustard seeds start to crackle and pop. Move on once the fenugreek has turned a deep brown and the aroma has risen. Burning it black brings bitterness, so have the tomatoes ready to add right away.

STEP 55 / 6

Break down the tomatoes, then add the potatoes and water

Tomatoes softly collapsing in the pan, with the potatoes and water added and brought to a boil — When the tomatoes have collapsed to a thick consistency, add the potatoes and water and simmer

Add the green chilies, the 1.5 cm diced tomatoes and 1 tsp salt and cook over medium heat for 5–6 minutes, mashing with a wooden spoon. When the tomatoes have lost their shape and collapsed to a thick consistency, add 1/2 tsp turmeric and 1 tsp Kashmiri chili powder, stir for 30 seconds and return the seared potatoes. Pour in 400 ml water, bring to a boil over high heat, then cook over medium heat for about 5 minutes, until a bamboo skewer slides easily into the potatoes.

STEP 66 / 6

Return the fish, simmer on low heat, and finish with lemon

Returning fish fillets to the thin tomato broth, simmering on low heat and squeezing lemon at the end — Simmer on low heat for 5–6 minutes and add the lemon juice after turning off the heat

Add 2 tbsp roughly chopped cilantro (about 5 mm) and gently return the seared fish to the broth. Simmer on low heat for 5–6 minutes, spooning the broth over the fish. It is done when the fish is white and opaque through its thickest part and the flesh flakes apart gently when pressed with chopsticks. Turn off the heat, drizzle in 2 tsp lemon juice, and mix by shaking the pan, taking care not to break up the fish. Serve in bowls and scatter the remaining cilantro.

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Ingredients

1 / 2

Fish seasoning and searing

Ingredient	Amount	Substitutes & notes
White fish fillets	8 pieces (about 600 g)	Cod, sea bass, Spanish mackerel, carp, etc.
Salt	1/2 tsp	—
Turmeric	1/2 tsp	—
Mustard oil (for searing)	3 tbsp	Edible grade
Potatoes	2	Cut into 8 wedges

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Broth

Ingredient	Amount	Substitutes & notes
Mustard oil (for the broth)	2 tbsp	—
Fenugreek seeds	1/4 tsp	—
Mustard seeds	1/4 tsp	Small brown mustard seeds are best
Nigella seeds	1/4 tsp	Kalonji
Dried red chilies	2	—
Green chilies	2	Slit lengthwise. 1 if you dislike heat
Tomatoes	4 (about 600 g)	1.5 cm dice
Salt	1 tsp	Adjust to taste
Turmeric	1/2 tsp	—
Kashmiri chili powder	1 tsp	Paprika also works
Water	400 ml	—
Cilantro	2 tbsp	Chopped. Save a little for garnish
Lemon juice	2 tsp	—

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In Assam's farming villages, fish raised in the pond behind the house goes straight into the evening meal. In the kitchen, fish fillets given a yellow base seasoning are fried in a pan filled with mustard oil, and into that same oil go a scatter of fenugreek and tiny black seeds. After the crackling and popping, chopped tomatoes go in all at once and the pot turns red. Soon what rises is the sourness of tomato and the sharp scent of mustard. This is masor tenga, the sour fish broth that people in Assam, in northeast India, have eaten over rice almost every day. In Assamese, "masor" means "of fish" and "tenga" means "sour."

Sourness has a name: the Assamese kitchen

An Assamese home table with rice, greens and a bowl of masor tenga for lunch

Assam is a land of rivers and wetlands, with the Brahmaputra flowing east to west. In Assamese cooking, fish is said to be the most important ingredient after rice, and many kinds of freshwater fish from rivers, ponds and lakes come to the table. In farming villages many households raise fish in their own ponds, and none of the traditional ethnic groups of Assam is said to avoid eating fish.

Compared with other parts of India, Assamese cooking is very restrained in its use of spices. In fish dishes, what matters is bringing out the taste of the fish itself. Masor tenga too uses only a few seeds and chilies for aroma, with the tomato's acidity and the fish's savor as the stars. The broth is thin and light, closer to a sour soup than a curry.

Did you know

Assam has many sources of sourness. The most common is tomato, but also used for tenga's acidity are the long, thick-skinned lemon "kaji nemu," dried "tekera" (a relative of mangosteen), the fruit called elephant apple, "ou tenga," as well as tamarind, star fruit and roselle leaves.

A traditional Assamese meal begins with an alkaline dish called "khar," made like baking soda, and the sour "tenga" was long regarded as something not to be eaten together with it in the same meal. In other words, alkaline and acid were eaten separately within one menu. Today that distinction has loosened, but the very fact that sourness has a name, tenga, says a lot about the character of the kitchen here.

What to know before you cook it at home

Mustard oil, fenugreek seeds, mustard seeds, nigella seeds, Kashmiri chili powder, tomatoes and white fish fillets

In Assam, freshwater carp-family fish such as rohu (rui) and catla (bahu in Assamese) are cut into rounds with the bone. In a home kitchen, fillets of firm white fish such as cod, sea bass or Spanish mackerel are easy to handle, and if you can get carp, it works too. Avoid fish with very soft flesh, which falls apart easily when simmered.

The base of the aroma is mustard oil. In Assam it is the cooking oil, with a sharp heat that goes up the nose. Choose one labeled as edible at an Indian grocery or online. The seeds used for tempering are three: fenugreek, mustard seeds and nigella seeds (kalonji). All are available at Indian groceries.

Tip

For the chili powder, Kashmiri chili powder, with its fine color and mild heat, turns the broth a bright red without making it too hot. In the recipe by the Indian chef Ranveer Brar, deggi mirch is used, a chili powder that likewise gives color with mild heat.

The method in this article is based on the Assamese-style fish curry presented by Ranveer Brar, adjusted to fillets and to 4 servings. The key to this method is to sear the fish and potatoes in mustard oil first and return them to the broth at the end for a short simmer.

Ingredients (serves 4)

White fish fillets, tomatoes, potatoes, green chilies, dried red chilies, spice seeds, mustard oil, lemon and cilantro for masor tenga

Caution

Mustard oil is pressed from the seeds of a plant in the same Brassicaceae family as mustard. People with a mustard allergy should avoid it. Putting wet fish or tomatoes into hot mustard oil makes the oil spatter, so wipe the fish dry and keep your face away from the pot as you add them.

How to make masor tenga

From seasoning the fish to finishing takes about 50 minutes in all. Because the fish and potatoes are seared before the broth is made, you can reuse the same pan.

Tip

After returning the fish, don't stir with a wooden spoon; spoon the broth over it from above. Even after adding the lemon, just rock the pan back and forth, and the fillets keep their shape well.

Caution

Cook the fish through to the center. Undercooked fish can cause food poisoning from parasites such as anisakis. For thick fillets, break open the thickest part with chopsticks to check that it is white and opaque through to the middle.

Over rice, light and flowing

Masor tenga spooned over white rice so that the broth soaks in — Spoon plenty of broth over the rice

Masor tenga is eaten with white rice. Spoon on plenty of the broth and eat it so that the tomato's sourness soaks into the rice. In hot weather, this sourness brings the appetite back. The heat is mild and the flavors of the fish and tomato come through straight, so people used to rich Indian curries will find it all the more fresh.

If you like the aroma of mustard oil, try shorshe ilish from neighboring Bangladesh. It is also a river-fish dish of eastern India, but it is simmered in a thick sauce of ground mustard seeds, a completely different taste. Nepal's choila (in Japanese) is also a dish that builds aroma with hot mustard oil.

Did you know

Fish stewed with fermented bamboo shoots, "khorisa", also has a sour taste, but in Assam this is not called tenga. Even among sour fish dishes, the name changes according to the source of sourness.

Variations

Masor tenga with thinly sliced ridged gourd added to the tomato and lemon

In Assam, seasonal vegetables are sometimes simmered together. In the masor tenga presented by the Indian web outlet The Quint, ridge gourd is paired with a fish called catla. In your own kitchen, cut ridge gourd, zucchini or eggplant 1 cm thick and add them at the same time as the potatoes, and they will soak up the broth and cook tender.

Reducing the tomatoes and strengthening the acidity with lemon juice gives a lighter, cleaner taste. Dissolving in a little tamarind changes it to a rounded sourness like another of Assam's tengas. Swapping the source of sourness to look for your own household's tenga is part of the pleasure of this dish.

FAQ

Leftover masor tenga moved to a storage container and refrigerated

What if I don't have mustard oil?

You can make it with vegetable oil, but you won't get the sharp aroma that makes it masor tenga. If you want to get close to the flavor of Assamese homes, I recommend getting mustard oil.

Can I use bone-in fish?

Bone-in rounds are actually closer to the Assamese way and give the broth more savor. You can also use chunks of carp or the collar and bones of yellowtail. Be careful of small bones when eating fish that have many.

Can I make it ahead?

Once it has cooled slightly, put it in a storage container and refrigerate, and finish it by the next day. As time passes the fish absorbs the broth and the flesh softens, so reheat gently on low heat.

How hot is it?

The green chilies and dried red chilies give a pleasant tingle. If eating with children, omit the green chilies and use 1 dried red chili. Kashmiri chili powder has only enough heat for color.

Sources

Ranveer Brar, "Assam style Fish curry | Masor Tenga Fish Curry." Accessed and checked 22 October 2026. https://ranveerbrar.com/recipes/assam-fish-curry/
The Quint, Tridip K Mandal, Muskan Singh, "Masor Tenga: Flavourful & Delicious Assamese Sour Fish Curry," published 26 August 2021. Accessed and checked 22 October 2026. https://www.thequint.com/neon/what-the-food/recipe-masor-tenga-fish-curry-desh-ka-tadka
Wikipedia, "Assamese cuisine." Accessed and checked 22 October 2026. https://en.wikipedia.org/wiki/Assamese_cuisine