In a mixing bowl, combine ground fish, egg, minced garlic, and salt. Mix well.
Gradually add tapioca flour and knead until a soft dough forms.
Shape the dough into small oval or round fish cakes.
Boil water in a pot and cook the shaped fish cakes until they float to the surface.
Remove and drain them, then let them cool slightly.
Heat oil in a pan and fry the fish cakes until golden brown and crispy.
Serve hot with sweet and sour vinegar sauce and fresh cucumber slices.