Scale and clean the fish thoroughly. Wash and pat dry them on paper towel. Cut them into pieces. Sprinkle little salt over the fish pieces and set-aside. Soak the tamarind pulp in 1 1/2 cups of hot water for 10 minutes. Strain and reserve the liquid. Mix the red chili powder, coriander powder and 1 tablespoon of water to make a paste. Heat 3 tablespoons of oil in a pan and fry the garlic and onions until soft. Add the fenugreek seeds and fry until an aroma comes from it. Then add the spice paste and fry for couple of minutes. Stir in the tamarind liquid and bring it to a boil. Now add the tomato paste and chopped tomatoes. Boil for 15 minutes. Check for salt and add if necessary. Then add the fish pieces. Lower the heat and cover the pan. Simmer for 10 minutes. Garnish with chopped cilantro leaves. Serve with white rice or Idlis (steamed rice cakes). This dish tastes even more the next day.