Parse Macher Aloo Diye Radhuni Batar Jhol Mullet and Potatoes cooked with Celery seed paste to make a Gravy

Parse Macher Aloo Diye Radhuni Batar Jhol
Mullet and Potatoes cooked with Celery seed paste to make a Gravy
Ingredients 
8 to10 whole Parse Fish cleaned
2 Potatoes cut lengthwise
2 tbsp Onion paste
4 tbsp Tomato paste
1/2 tsp Garlic paste
1/2 tsp Ginger Paste
2 to 3 Green chillies slit
Salt to taste
1 tsp Tumeric powder
1/4 tsp Chilli powder
For the paste grind (1 tsp Radhuni (Celery seed),  1 tsp Mustard seeds, 1/2 tsp Coriander seeds, 1/2 tsp Cumin seeds)
1/4 tsp Nigella (Kalonji) seeds
1/2 cup Mustard oil for fry                  

Method
Apply 1/2 tsp turmeric powder and salt to the fish and keep it aside for 5 minutes. Heat the mustard oil in a wok. Fry the fishes till light brown on both sides. Keep the fish aside. Let 3 tbsp oil remain in the wok and take rest of the oil out. Add the Kalonji seeds and green chillies. Add the onion paste, garlic and ginger paste. Sauté it for 2 minutes. Add the tomato paste, salt, 1/2 tsp turmeric powder, chilli powder, ground paste. On a low flame, stir, cover and cook for 2 minutes, stir in between. Add the potatoes and cook for another minute. Add 2 to 4 cups of water depending on the gravy wanted. Cover the lid and cook till the potatoes are done. Add the fish. Simmer for another 5 to 7 minutes.. Serve hot with hot steaming rice.