I got this recipe from an old recipe book.
It's a Cantonese soup called "Sang Choi Yue Pin Tong". According to the writer, she uses fresh carp but it's equally OK to use sole, flounder or sea bass.
1/2 pound fresh fish, sliced thinly
Marinate fish with 1/4 tsp salt, 1/2 tsp sugar, 1 tsp sesame oil, 1/4 tsp cornstarch, 1 tsp ginger juice mixed with 1 tsp white wine, some pepper and 1 tsp light soya sauce. Let it sit in the marinade for 10 minutes.
In a pot, bring to boil 3 cups water. If you have fish stock, even better. It will be tastier, says the writer. Add to this pot 1 slice of ginger and 1 clove garlic. Add lettuce, stir and add in fish slices (together with marinade). Bring to boil. Turn off heat and stir in some scallion oil. Serve hot.
How to make scallion oil:
In 2 cups peanut oil, add 1 cup of the whisker/root ends of scallions and 2 cups of scallions (spring onions). Heat wok. Pour this into wok and heat until scallions brown. Strain oil and discard scallions. Allow to cool completely before storing in a jar. Use as needed. Scallion oil is delicious when a teaspoon or so is stirred into dishes.
So there you have it. A quick soup you can make in less than 15 minutes. My kind of soup!