Marinate the fish with lemon juice, ginger-garlic paste for fifteen minutes. Grind together green chilli, mint leaves, coriander leaves and curry leaves to a fine paste with a little water if necessary.
Add this paste, yogurt, one tablespoon oil, white pepper powder and salt to the fish and mix well. Set aside to marinate for a further thirty minutes.
Coat the marinated fish pieces with rice flour and dust-off the excess flour. Heat oil in a non-stick pan. Place the fish pieces on it, a few at a time, and cook, turning sides, till crisp and evenly done from both sides. Serve hot.