1. Cut fish into large pieces, keeping the skin on if possible.
2. in a medium sized sauce pan, heat oil over medium to medium high. Add onions and brown.
3. Add dry spices (exluding Ajwain seeds) to the onions, fry for 1 minute. Add ginger-onion-garlic paste and fresh tomatoes and fry for at least 3 minutes, or until tomatoes start to break down.
4. Add tomato paste, tamarind paste, curry leaves and 1/2 the ajwain seeds. Fry for 4 minutes, or until paste really starts to thicken.
5. Add a few tbsp of water to your masala paste (this is to make the masala liquidy enough for the fish to poach in it). Stir well, and add the fish chunks, one by one, ideally separated by a few cm, skin side down.
6. Cook for 90 seconds, or until sides of fish start to look lighter in color. Flip once and cook for another 90 seconds until fish is done.
7. Serve over steamed rice or with whole wheat chapatis.
Trout has a thin filet and would cook quicker than other varieties like salmon steaks.
Feel free to add a few tbsp of coconut milk or sour cream to make a slightly creamy curry.