Marinate the fish with turmeric powder and salt.
Thinly slice the garlic and mince green chilies
Gather all your other ingredients.
Heat oil in the pan and add fish skin side down. Cook for one to two minutes depending on the thickness of the fish.
Flip the fish to cook the other side. Cook for one to two minutes. Remove from heat.
To the same pan, add nigella seeds and cook for 30 seconds. Scrape the bottom of the pan to loosen any fish bits sticking.
Add thinly sliced garlic and minced green chilies and fry for 30 seconds.
Add Kashmiri red chili powder and turmeric powder and cook for 30-45 seconds. Lower the heat if required. Do not let the spices burn.
Add ½ cup water and cook until the sauce thickens. This would take about 3-4 minutes.
Now add 1 cup of hot water, salt and bring to boil.
Add the fish pieces, cover, and cook for 5 minutes or until the fish is cooked through.
Make a smooth slurry with all-purpose flour and 2-3 tablespoons of water. Add slurry to the curry and cook for another 2 minutes.
Serve hot garnished with finely chopped cilantro.