Separate the flesh from the skin and bones. Put into a ziplock bag.
Use a roller to roll the flesh till it become paste.
Push the paste and add 1 tbsp cold salted water (1tbsp salt and got water, dissolve n freeze for 1/2 hr), 1 tbsp of corn flour and some dashes of pepper. Now use your hand to knead. (Hand outside of plastic bag.) Knead about 5 mins will do. This way your hands r totally clean.
Flatten the paste again and send it to the chiller to chill for at least 30mins. This is for setting. Must flatten, do not chill in round dough form.
Now fill a bowl with water and salt. Wet your hands, scoop the fish paste. It is easier to handle and the surface will be smooth. Pinch a small ball and make it round by squeezing it to firm it. Put into the boiling soup.