Mix together maida, pepper powder, ginger-garlic paste, salt and beaten egg white into a smooth paste.
:- You can add little water if required.
Marinate the fish pieces with above made paste for 1 hour.
Heat oil in a pan and deep fry the fish pieces to a golden brown color.
Pour the remaining oil into another pan and sauté onion, chopped ginger, chopped garlic for 2 minutes on low flame.
Add chopped capsicum, celery and green chillies. Stir and simmer for 1 minute on low flame.
Add tomato sauce, soya sauce, salt and chilly sauce and sauté it for 2 minutes on low flame.
Add vinegar and mix gently.
Allow the gravy to boil.
:- If you need thickness for gravy, just mix 1 tsp maida in 1/2 glass water and add it in gravy and stir it for 1 minute.
Add the fried fish pieces to the gravy and simmer on low flame for 2 minutes.
Add chopped coriander leaves and switch off the flame.
:- Serve hot.