CC license
Ingredients:

1/2 stalk of Lemon grass.
3 kaffir lime leaves, washed
1 tbs uncooked rice, washed, drained
1 small size of fresh sea bass, catfish, scaled, washed and cut.
1/2 green onion, chopped
600 ml (2 1/2 cups) of  water
415 ml (1 can, 14 oz) of chicken, fish or mushroom broth, 
green mango, peel the skin and grate.
1 clove of garlic, minced
Khmer basil, (chee neang vong)  washed and cut
Khmer coriander, (sangkahum) washed and cut
1 tsp fish sauce
a pinch of salt
a pinch of sugar
a pinch of granulated mushroom bouillon
 

Method:
 
1) Put water, lemon grass, rice and kaffir lime leaves in a medium pot.  Cover and bring to boil. Stir well. Make sure the rice grain doesn’t stick to the bottom. Cook until soft.     
2) Then add chicken broth.
Add fish, some salt, chicken bouillon, sugar. Cover and bring to boil.     
3) Stir carefully. Do not break the fish texture. Add mango, garlic and fish sauce. Bring to first boil.*Turn off the heat and garnish it with herbs, green onion and a fresh chillie floret.
 
If green mango is naot available or if the flavour is not sour enough then the addition of a little lime juice will be effective.
Traditionally this soup is served with fish sauce and chili. In a small bowl, pour in some fish sauce, some lime juice, sugar and finely chopped 1 fresh chili.