Soak the tamarind for 30 min
Wash and clean the fish..and add turmeric powder and keep it aside
Grind coconut and 2 small onion to make smooth paste
Heat oil in a pan add mustard seeds, fenugreek, curry leaves
Add chopped onion, garlic and saute it for 1 min
In a bowl add prepared coconut paste, chopped chillies, chopped tomato, chilli powder, coriander powder, salt, tamarind extract and mix well
Add the above mixture to the pan and cook for 15 min on medium flame
Add fish pieces and cook for 15 min on low flame or until oil separate from sides