Clean and wash the fish. Marinate with turmeric powder, salt and red chilli powder. Keep aside.

Take mustard in a grinder jar. Grind to powder with intermittent pulse. Add one red chilli and garlic cloves and 1/4 cup water. Make a smooth paste. Set aside.

Fry the marinated fish with mustard oil. Add rest of the oil. Crackle ponch phutan and add chopped onion and red chilli. Fry the onions.

Onions and chopped tomatoes. Fry till tomatoes are softer. Add chopped potatoes, salt and turmeric powder. Saute on low flame for 2 minutes.

Now, add the mustard seeds paste with required water for the gravy. Bring to boil and drop the fried fish as much required. Simmer for two minutes on low flame and serve with steamed rice.