First, bring water to rapid boil, add snake fish cutlets to boil until cooked and scope out the snake fish cutlets to cool down. Save the stock for the soup base. Second take 2-3 cutlets of the snake head fish, debone and pound together with sour soup paste until thoroughly. Third dissolve the sour soup paste that have pounded together with snake head fish meat, bring to the boil and simmer over high heat for 5 minutes. Add Sam Choi, Chinese radish and string bean, Finally season with palm sugar, fish sauce and concentrated tamarind juice and leave it to boil. Add the rest of snake head fish cutlet, when it back to the boil turn off the heat.