Marinate the cleaned fish in a mixture of: 1 tsp crushed pepper, 1/2 tsp turmeric powder , ¾ tsp salt and 1 tsp lemon juice. Keep it aside for at least 30 minutes.
Meanwhile, heat 3 tablespoon of coconut oil in a large pan over medium-high heat. Once the oil is hot, arrange the fish in a single layer and fry for 3-4 minutes on each side until lightly browned.
Transfer the fried fish to a plate and keep it aside.
To make the curry, pour 2 tbsp Coconut oil into the same pan, add cardamom, cinnamon stick, clove, chopped ginger, garlic and green chilly. Saute for 10-15 seconds.
Add onion and salt, fry till onion turns pinkish.
Add coriander powder and turmeric powder and saute for 10 -15 seconds. Then add fried fish pieces.
Pour thin coconut milk and pepper powder. Keep the flame on medium. Add chopped tomato, cover the lid and cook for 4-5 minutes.
Finally, reduce the flame and pour the thick coconut milk and vinegar. Stir very slowly and carefully. Do not bring it to boil, turn the flame off before it starts to boil.
Fish Molly is ready now.