Apply salt to fish pieces and set aside for fifteen minutes. Soak kokum in half a cup of hot water for fifteen minutes. Strain and use the water.
Grind tirphal in a quarter cup of water and strain. Use only the water. Grind the red chillies with coriander seeds, coconut and turmeric powder to a fine paste with half a cup of water. Add the tamarind pulp, triphal water and one tablespoon of oil.
Apply this masala to the fish pieces and set aside for half an hour. Heat the remaining oil in a non stick pan. Add the fish pieces along with the masala and sauté for one minute. Add half a cup of water.
Reduce heat, cover the vessel with a lid and pour a little water over it. Cook for ten minutes and remove lid. Add kokum water and bring to a boil.
Add more water if necessary for the gravy should be quite thin. Adjust salt. Garnish with coriander leaves and serve hot with steamed rice.