Clean and wash the fish and keep aside.
Mix together the ingredients for the masala with a little water and make it into a paste.
Heat oil in a pan or a kadai.
Add curry leaves and onion and saute.
When it turns translucent, add tomato and saute well.
When it becomes a bit pulpy, add the masala paste.
Fry, till the raw smell goes and the oil starts to separate.
Add tamarind pulp and a cup of water.
Allow it to boil.
When the gravy becomes a bit thick, add salt.
Add fish and cook, till the fish is done.
:- Serve hot with rice or cooked kappa.