Filipino Fish Soup: Tamarind Sinigang with Vegetables

Filipino fish soup, often made as sinigang na isda, is a sour, savory soup of tender fish, vegetables, and tamarind broth. The balance of tangy tamarind, fish sauce, and fresh vegetables makes it lively but comforting, and the many regional and family versions can use different fish or souring ingredients.

Ingredients

1½ lb (680 g) firm white fish steaks, about 1 inch (2.5 cm) thick, preferably bone-in; see Tips for fish choices
8 cups (1.9 L) water
2 tbsp (30 g) tamarind concentrate or seedless tamarind paste
1 medium yellow onion, about 5 oz (150 g), peeled and cut into wedges
2 medium ripe tomatoes, about 10 oz (300 g), cut into wedges
1 inch (2.5 cm) fresh ginger, about ½ oz (15 g), thinly sliced
3 garlic cloves, about ⅓ oz (9 g), lightly crushed
1 tbsp (15 ml) neutral cooking oil
1 tbsp (15 ml) fish sauce, plus more to taste
8 oz (225 g) daikon radish, peeled and cut into ½-inch (1.3 cm) half-moons
8 oz (225 g) Japanese eggplant, cut into 1-inch (2.5 cm) pieces
6 oz (170 g) green beans, trimmed and cut into 2-inch (5 cm) lengths
1 small green chili, about ⅓ oz (10 g), whole or slit, optional
4 oz (115 g) water spinach, also called kangkong, cut into 3-inch (7.5 cm) lengths; or baby spinach
½ tsp fine salt, about 3 g, plus more to taste
¼ tsp ground black pepper, about ½ g

Instructions

Prepare the fish and vegetables. Cut the fish into four portions if needed, pat it dry, and check for loose scales or stray bones. Keep it chilled while you prepare the vegetables. Cut the onion and tomatoes into wedges, slice the ginger, and prepare the daikon, eggplant, beans, chili, and greens. The fish should be close to 1 inch thick so it cooks in the time given; thicker pieces may need a few additional minutes.
Start the broth, 4 minutes. Heat the oil in a large, heavy pot over medium heat. Add the onion, tomatoes, ginger, and garlic. Cook for about 4 minutes, stirring occasionally, until the onion starts to soften and the tomatoes begin to release their juices. They do not need to brown; keeping the heat moderate helps the garlic stay sweet rather than scorched.
Simmer the base, 10 minutes. Pour in the water and add the tamarind concentrate, fish sauce, salt, black pepper, and optional chili. Bring the liquid to a boil, then reduce the heat to maintain a steady, gentle simmer for 10 minutes. Taste the broth before adding the fish. Tamarind products differ in strength, so if the soup is not tangy enough, stir in another teaspoon of concentrate; if it is too sharp, add a little water.
Cook the sturdy vegetables, 7 minutes. Add the daikon and simmer for 4 minutes. Add the eggplant and green beans, then simmer for about 3 minutes more. The daikon should be starting to turn tender, while the beans and eggplant still hold their shape. If your pieces are particularly thick, give them an extra minute before adding the fish.
Poach the fish, about 9 minutes. Lower the fish portions gently into the simmering broth, spacing them out. Keep the liquid at a gentle simmer rather than a hard boil, which can break up the fish. Cook for about 7 to 9 minutes, turning the pieces once only if needed. Check the thickest part of a portion with a food thermometer: USDA FSIS lists 145°F (63°C) as the safe minimum internal temperature for fish. If it has not reached that temperature, continue cooking and check again after a minute or two.
Finish the soup, 2 minutes. Add the water spinach and cook just until the leaves wilt and the stems turn bright green, usually 1 to 2 minutes. Taste the broth and adjust with a little more fish sauce for savoriness, salt if needed, or a small amount of tamarind for extra sourness. Serve carefully so the fish stays in large pieces, with broth and vegetables in every bowl.

Tips

Choose fish that holds together. Bone-in steaks of milkfish, snapper, grouper, or salmon work well, as do thick pieces of cod or halibut. Milkfish is a familiar choice in Filipino cooking but can be hard to find; snapper or another firm white fish is a practical substitute. Delicate thin fillets can flake apart, so add them later and shorten their cooking time while still checking for 145°F (63°C).
Adjust sourness gradually. Tamarind paste and concentrate vary by brand and preparation. Add the first amount, simmer, and taste before increasing it. If using a packaged sinigang soup mix instead, follow its package quantity for the amount of broth and reduce or omit the added salt and fish sauce at first; mixes often contain salt and can make the broth more seasoned than a concentrate does.
Keep the pot at a gentle simmer. A rolling boil can make fish steaks bump into each other and break apart. Lower the heat after the broth comes to a boil, then slide the fish into the liquid instead of dropping it from a height. A wide pot gives the portions room and makes it easier to serve them intact.
Use the greens you can find. Water spinach, or kangkong, has tender leaves and crisp stems, but it is not stocked everywhere. Baby spinach is convenient and wilts quickly; bok choy leaves are another option, though they make the soup less traditional in character. Add any substitute near the end so it does not become dull and overcooked.

Serving Suggestions

Serve the soup hot in deep bowls, making sure each serving gets fish, several vegetables, and plenty of broth. Steamed white rice is the usual partner for a sour soup like sinigang: spoon some broth over the rice, or eat the rice alongside it so it can soak up the tangy liquid. A small dish of fish sauce with sliced chili lets diners season their own portions, but taste the soup first because the broth already contains fish sauce.

This is a complete meal with rice, though a simple side of sliced cucumber or a plate of fresh tomato can add a cool contrast. If serving several people, bring the pot to the table and lift the fish out with a wide spatula or serving spoon rather than stirring repeatedly. The fish is tenderest just after cooking, and gentle handling preserves the portions.

Variations

Use a different souring ingredient. Tamarind gives the broth its recognizable rounded tang, but Filipino sour soups also vary by household and location. Green mango can provide a fruity sharpness, while calamansi or another sour citrus gives a brighter, more delicate taste. Add citrus juice near the end and start with a modest amount, since it tastes different from simmered tamarind. These changes make a related sour fish soup, not an exact tamarind version.

Change the vegetables. Mustard greens, bok choy, radish greens, or sliced green papaya can stand in for some of the vegetables here. Add firm vegetables early enough to soften, and put leafy greens in at the end. Okra is another possible addition; its texture makes the broth slightly thicker. Keep the total quantity of vegetables close to the recipe amount so the pot does not become crowded or dilute the broth.

Make the broth more or less spicy. Leave the chili whole for a mild, subtle warmth, slit it for more heat, or omit it altogether. For extra heat at the table, serve sliced chili separately rather than making the entire pot spicy. You can also use a different firm fish or a mixture of fish, but keep the pieces similar in thickness so they finish cooking at roughly the same time.

Storage and Reheating

Refrigerate leftover soup within 2 hours of cooking. Transfer it to a covered, shallow container so it cools promptly, and keep it refrigerated for 3 to 4 days. Fish can become more fragile after storage, so portion the leftovers gently and avoid repeatedly warming and cooling the whole pot.

For longer storage, freeze the soup in airtight, freezer-safe containers for up to 2 months for best quality. The vegetables may soften and the fish may flake more after thawing, but the broth remains useful. Thaw overnight in the refrigerator rather than on the counter.

Reheat only the portion you plan to eat in a saucepan over medium-low heat, stirring the broth gently and turning the fish carefully. Heat leftovers to 165°F (74°C), checking the broth and a substantial piece of fish with a food thermometer. Avoid a vigorous boil, which can break up the fish. If the broth tastes more concentrated after storage, add a splash of water and adjust the seasoning after reheating.

Frequently Asked Questions

What fish is best for Filipino fish soup?
Choose a firm fish that stays in large pieces during simmering. Milkfish is a traditional and widely used option, but its bones require care and it may not be easy to find. Snapper, grouper, salmon, cod, or halibut can work; bone-in steaks add flavor, while thick boneless portions are easier to eat. Avoid very thin fillets unless you shorten the cooking time and handle them gently.

Can I make this soup without tamarind?
Yes. A packaged sinigang mix is a convenient substitute; use the amount specified for a similar volume of broth and season cautiously because it may already contain salt. Green mango or a little sour citrus can also make a pleasing sour broth, but each has a different flavor. If you use citrus, stir it in near the end rather than simmering it for the full time.

How do I know when the fish is done?
Check the thickest part with a food thermometer. Fish is safely cooked at 145°F (63°C), the USDA FSIS safe minimum, and the flesh should look opaque and separate readily into flakes. Do not rely only on the outside color, especially with a thick steak; continue simmering briefly and check again if the center has not reached temperature.

Can I prepare the soup ahead?
You can chop the vegetables and portion the fish a day ahead, keeping them in separate covered containers in the refrigerator. The broth can also be made ahead and chilled, then brought back to a simmer before the vegetables and fish are added. For the best fish texture, cook the fish shortly before serving instead of simmering it, cooling it, and reheating it later.

Why is my broth too sour or too salty?
Tamarind concentrates differ, and packaged soup mixes may include salt, so seasoning can vary even when you measure carefully. If the broth is too sour, dilute it with a little hot water and taste again; adding more fish sauce will not remove the acidity. If it is too salty, add water and a few unsalted vegetables, then recheck the flavor. Next time, begin with less concentrate or seasoning and adjust at the end.

Can I use frozen fish?
Yes. Thaw it in the refrigerator, then pat it dry before adding it to the soup. Frozen fish sometimes releases extra moisture, so a gentle simmer and careful handling are especially helpful. Do not add a solid frozen block to the pot, because it can cool the broth unevenly and make it harder to cook the fish consistently. Check the thickest portion with a thermometer before serving.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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