In soup pot boil water with sliced of onion and garlic,add a whole fish or use 2 fish fillet instead is fine,dont stir this..let it boil for approximately 20 mins,heat off ..transfer fish,garlic and onion to the tray..let it cool
Shelled watermelon,first trim the green part ,then slice off only white part of the shell,slice into bite size ,set aside..oh ..bring watermelon to chill in your refrigerator too !
Drain fish soup into new pot (protect from loosed fish bone in the soup ),set on medium heat ,add watermelon's shell..reduce to simmer after bouble boil ,spoon out boubles on soup surface
While simmering ,make chiili paste ,by pestel and mortar or blender,mix well paste ingredients then add fish fillets or deboned fish
Add fish paste into soup pot,seasoning,stir to mix ,let it cook another10 mins
Taste it ..you will find the mildy sweet and sour soup ..add shrimps,3 more mins cook,then heat off,serve hot with steamed jasmine rice :)