Steam fillet until cooked. Let it cool then flake the fillet.
Combine onion, sweet potato, black pepper and salt until all the ingredients are thoroughly mixed.
Form two teaspoons of mixture into a ball and shape into nuggets.
Do the same thing to the rest of the mixture.
Roll in flour each nuggets and dip in beaten egg then roll in bread crumbs.
Deep fry until golden brown and serve hot with sweet and sour sauce or chili sauce or tartar sauce.