To prepare a tamarind and pineapple fish soup recipe, you will first need to gather your ingredients. You will need the following ingredients: 1 cup (240 ml) water, 1 tbsp (25 g) sugar, and 1 teaspoon (2.5 mg) salt. Bring the water to boil, then reduce the heat to medium-low and simmer the mixture until the sugar dissolves, about 5 minutes. Remove the pan from heat and add the fish to the pot. Cover the saucepan and cook the soup for 20 minutes, stirring occasionally. Serve with sour cream, if desired.