Wash the fish pieces and pat them dry. Rub half tsp of turmeric powder and a little bit of salt to the fish.
In a frying pan or kadai, take 2 tbs of mustard oil. Heat the oil till it almost reached a smoking point and then gently slide the fish pieces into the pan to fry them.
Fry the fish on each side for less than a minute. Just a little bit of golden colour would do.
Take the fish out of the oil and keep aside.
In the same oil, add another half tbsp of mustard oil. Heat it and add panchphoron and break a couple of green chilies into it.
Stir it around on medium heat till you get the panchphoron fragrance.
Take one cup of milk and dissolve the rest of the turmeric powder into it. Also dissolve the red chili powder into it, if you are using it.
Add this milk to the oil. Keep the heat low and let it simmer for about 4 to 5 minutes.
Then slide in the fish. Add another half cup of water, add salt to taste and let it come to a boil. Then lower the heat, cover and cook for 5 minutes. Let the oil come out of the gravy.
Uncover, drizzle 1 tbsp of mustard oil and add a couple of split green chilies.
Turn off the heat and serve doodh maach with steamed rice.