Cut the fish to desired size pieces (about ¾ to 1 inch) or to strips and rinse and drain completely.
Pour the lemon juice and salt over the fish and set aside for 5 minutes.
Marinate with red chillii powder, turmeric, salt,, ginger garlic paste & egg white. Set aside for about 30 minutes.
Heat oil for deep frying on a medium heat.
Sprinkle corn flour and all-purpose flour. Mix well to coat them.
When the oil is hot enough, reduce the heat to medium, deep fry the pieces until crisp and golden. Remove to a cooling rack or a colander.
Heat 1 tbsp. oil in another pan. Fry curry leaves till crisp, add ginger garlic and green chilies and fry till you get an aroma.
Add chopped onions and fry till lightly brown. If you want you may add soya sauce and mix well. Add the fried fish and saute on high for 3 mins.
Apollo fish fry is ready.