Insert a knife into the anus near the tail of a mud carp; Draw the knife toward the head, splitting the fish to the base of the gills; Spread the abdominal cavity with fingers; Reach in and pull out the entrails; Rinse the cavity under running water; Cut off the head with the knife; Rinse the fish under running water again; Pat-dry the fish with kitchen paper.
Lay the mud carp horizontally on the cutting board with the back of the fish facing you; Position a filleting knife behind the gills and cut downward at a slightly diagonal through the bone to cut off the head; Place the knife down where the tail meets the body and cut straight down through the skin and the bone of the fish to cut off the tail.
Insert the knife behind the gill cover of the mud carp and cut downward till the knife hits the backbone; Turn the knife so that it is aligned with the ribcage and push it down so that the tip extends about midway down the fish’s body; Run the knife along the ribcage to separate the meat from the ribs; Pull the meat away from the ribcage (repeat the step for anther side).
While holding a piece of fillet steady on a plate with on hand, remove any tiny pin bones with a needle-nosed pliers; Position the knife between the skin and the flesh; While holding the skin tightly with one hand, angle the knife slightly and slide it through the length of the fish fillet to separate the skin from the flesh; Cut the flesh into dices (repeat the step for the other fillet).
Chop the fish flesh finely with a cleaver.
Rinse and drain spring onion; Cut off any roots; Chop it finely with the cleaver.
Rinse ground pork under running water; Drain it; Put it in a big mixing bowl; Add the fish flesh, seasoning (1) and most of the spring onion; Stir it clockwise until sticky (about 10 minutes); Cover the bowl with cling film wrap; Chill it in the fridge for 1 hour; Take the bowl out of the fridge; Discard the cling film wrap; Stir it clockwise again for 1 minute; Put a portion of the fish mixture on a hand and roll it into a ball (repeat this process till the pork mixture is used up).
Rinse winter melon under running water; Scrape out the seeds; Peel it with a Y-shaped peeler; Cut it into chunks.
Rinse, drain, peel and slice ginger.
Rinse salted turnip under running water; Drain it; Cut it into sticks.
Add 1 tbsp, the ginger and the salted turnip oil into a nonstick wok; Stir-fry them over a medium heat till fragrant; Add the winter melon and seasoning (2); Bring to the boil over a high heat; Cook over a high heat for 5 minutes; Add the fish balls; Bring to the boil over a high heat again; Cook over a high heat for 8 minutes; Turn off the heat; Arrange it in a serving bowl; Garnish it with the remaining spring onion; Ready to serve.