Clean the fish pieces well. Apply turmeric and salt and rub thoroughly.
Let it rest for 5 min and then rinse it well. Keep it aside.
Cut garlic, onions, tomatoes roughly. slit green chillies.
Soak tamarind in Luke warm water for some time. Extract juice and remove pulp.
Heat sesame oil in a kadai over medium heat.
Temper with cumin seeds, mustard seeds, fenugreek and pepper.(Crush pepper)
Add garlic, curry leaves, green chilli and red chilli.
Saute for less than a min. Add onions
Cook until they become soft. Add ginger garlic paste and tomatoes.
Saute until there is no raw smell.
Add turmeric, red chilli powder, salt and coriander powder. Combine well.
Add tamarind extract. Combine well and cover the kadai with a lid.
Cook until oil oozes out on the top. Add coconut paste and cook for 3 min.
Add fish pieces. Crush 2 shallots and add it along with fish.
Cook for 4 min and flip the fish pieces. Cook for another 4 min.
Turn off the heat and garnish with coriander leaves.
Adding crushed onions at the end gives unique flavor to the curry.
Cooking time of the fish differs according to the size of the fish pieces.
You can use any oil but sesame oil gives very good taste for this kuzhambu.