Mix glutinous rice flour with boiled sweet potato. Shape the mixture into balls, filling each with mashed, cooked mung beans. For the fish shapes, use the same method and press into a mold if desired. Color the balls and fish shapes as you like. Boil them in water until they float to the surface, then remove.

Make a sweet syrup by simmering sugar with enough water and adding julienned ginger. Add the cooked dumplings and fish shapes to the syrup. Serve in a bowl so the fish shapes appear to swim among the dumplings. Sprinkle toasted sesame seeds on top.