1. Wash fish & add 2 tbsp salt & tsp turmeric - toss & leave to marinate for 30-45 mins.
2. Grind the coconut, red chillies, pepper, jeera/cumin, turmeric/haldi, coriander seeds, onion & garlic with water to a smooth paste.
3. Chop tomatoes & place in a thick-bottom vessel with oil; then, heat it.
4. When it is soft, add the ground masala 2 tbsp at a time, stirring constantly & frying well in between.
5. Add 1 cup water & leave to boil.
6. Wash fish well & add to boiling gravy.
7. Then add the tamarind, slit chilli & vinegar & simmer open until fish is cooked.

Hint: Keep some washed fish pieces aside to fry: Toss them with 1/4-1/2 tsp each of pepper, turmeric, cumin & red-chilli powders & shallow fry.