Sour fish soup is a beloved dish, especially during the summer months. However, many are hesitant to cook fish soup due to the strong fishy odor that can be challenging to mask if not prepared properly.
With the right preparation, sour fish soup can be delightfully sweet and free from any fishy odor. Additionally, this dish is quick and easy to prepare.
Selecting Fresh Fish
One of the most crucial factors in determining the taste of the dish is the freshness of the fish. The fresher the fish, the less likely it is to have a strong odor, and the more natural sweetness it will possess. Choosing and preparing fresh fish will ensure your soup is delicious without the need for complicated cooking techniques.
Regardless of the type of fish you choose, always select those that are lively and vibrant with intact, firmly attached scales. Look for pink gills and clear eyes. If purchasing pre-cleaned fish, press your finger into the flesh to test for firmness and elasticity. Fresh fish will spring back without leaving an indentation.

Fish Preparation
Proper fish preparation involves removing any slime and neutralizing the fishy odor. There are several effective methods to clean your fish.
Start by scaling, gutting, and removing the fins and gills. Pay particular attention to scraping away the thin, dark membrane inside the abdomen, as this is a key source of the fishy odor.
Subsequently, you can rinse the fish with water mixed with rice starch and a pinch of salt. This traditional method, passed down through generations, effectively removes both slime and odor.
Alternatively, you can use salt, vinegar, or lemon juice, rubbing it inside and out, to neutralize odors and remove slime. Another effective method is to apply crushed ginger and a splash of alcohol to the fish.
For a different approach, try using cooking oil. After removing the blood clots and the dark membrane from the abdomen, rub the fish inside and out with salt for about 5 minutes, then rinse with clean water. Follow this by massaging cooking oil into the fish for about 2 minutes, and then give it a final rinse.
After cleaning, allow the fish to air dry before cooking. Meanwhile, you can prepare the other ingredients. Typically, sour ingredients such as tomatoes, sour fruit, tamarind, fermented rice paste, or sour bamboo shoots are used to create the distinctive sour flavor of the soup. Choose according to your preference and availability.
Common seasonings for fish soup include salt, fish sauce, pepper, chili, and various herbs such as dill, coriander, and spring onions.
Cooking the Sour Fish Soup
Depending on your preference, you may choose to fry the fish before adding it to the soup. Frying the fish will result in a firmer texture and a golden-brown exterior. This step also helps prevent the fish from disintegrating during the cooking process. However, frying adds more oil and fat to the soup, resulting in a richer and more indulgent broth.
If you prefer a lighter, sweeter, and more natural-tasting soup, you can skip the frying and add the fish directly to the pot. Start by sautéing some spring onions and diced tomatoes, along with your preferred seasonings. Once the tomatoes are soft, add water and bring it to a boil. Tomatoes not only add a subtle sourness but also give the soup a beautiful red hue. If using sour fruit or tamarind, add them at this stage as well.

When the water boils, add the fish and simmer for about 10 minutes, seasoning to taste. It’s important to only add the fish to boiling water; using cold water will result in a fishy odor. You can also add other quick-cooking vegetables such as okra, ridge gourd, or bean sprouts. As these ingredients cook quickly, keep an eye on them to avoid overcooking.
Once the fish has absorbed the flavors, add a sliced chili pepper if you enjoy a spicy kick. If you prefer a milder heat, simply add the chili stem to the soup without slicing the pepper.
To enhance the sourness and add a unique flavor, stir in a tablespoon of fermented rice paste or sour bamboo shoot juice.
Finally, when the fish is cooked through, add the herbs—dill, coriander, and spring onions—and your sour fish soup is ready to be served!