First fish marination for red chili powder, turmeric powder, and Lemon juice, Salt to taste.
Mix very well and keep it leave 10 min.
Add 1/4 cup of oil and fry all the fish pieces in a pan and fry until lightly golden, keep it out on another plate.
FOR GRAVY:
In the same pan add oil, mustard seed, and whole cumin seed and saute for 1 min, Now add ginger garlic paste, red chili powder, coriander powder, turmeric powder, and
salt to taste.
Mix well and saute for 2 min add yogurt, and fried onion mix well.
Now time to add all the fried fish pieces and 1 cup of hot water.
Cook for 7 to 8 min.
Garnish with fresh chopped coriander leaf and green chili.