Fillet the fish on both sides and cut the fillets into one inch cubes.
Add ginger-garlic paste, red chilly powder, lemon juice, salt, turmeric powder and rice flour to the fish pieces. Mix carefully and allow to marinate.
Take all purpose flour(maida) and egg white into a bowl and mix well. Add half tea spoon of salt and mix again. Prepare slightly thick batter adding slight water, if necessary.
Add the marinated fillets to the batter and allow to settle.
Take oil into a deep bottomed frying pan and boil.
Transfer the fish pieces with enough batter on them into the corn flour.
Now add each piece to the boiling oil and fry in medium flame until crispy and brown in color.