In a bowl, add the fish, lemon juice, cumin powder, salt and mix. Let the fish marinate for 10 - 15 minutes.
In a medium pan on medium / low heat, add the olive oil and sliced onion. Cover the pan and allow the onions to cook for 4 minutes.
Then add the spices ( caraway, cumin, cayenne and paprika powder) to the onions and stir. Add the jalapeños and cook for 2 minutes.
In a separate bowl, add the tomato puree, tomato paste, minced garlic, spices and mix.
Add the tomato mixture into the pan and stir. Let the mixture to come to a very light simmer and then add the hot water and then add the potatoes. Cover the pan and let the potatoes cook ( 10 minutes depends on how large you cut the potatoes)
Once the potatoes have cooked through, place the fish fillet one at a time and cover the pan and allow the fish to cook. This will take anywhere between 8-12 minutes. Again it depends on how large and thick your fillet is.
Once the fish has cooked and is firm to the touch, remove the pan from the heat and serve the fish stew with a side of bread and enjoy!