Do not put oil in the soup. Maybe there is some oil floating on the fish soup you drank. That's because if you want crucian carp soup to be milky white, you have to fry the fish first, which will also remove the fishy smell. Just like cooking, it's best to fry the fish everywhere until it turns brown slightly. Boil the water, be sure to put it in a pot with boiling water. The soup will soon turn white, really milky white. Generally, I want the soup to be white and thick and simmer for half an hour. Haha, the soup is white and thick, but the fish is a little rotten. When it is ready, put salt to prevent iodine loss. It is delicious and white. Put the soup in a bowl and sprinkle with chopped green onion. It is best not to sprinkle shallots directly in the pot. If the temperature is too high, it will smell like rotten onions. If you can't finish a meal, the rest will smell like rotten onions after reheating, and so will parsley. Depends on whether you like leeks or coriander. O(∩_∩)o ... haha laughed