Indian
Rub the fish steaks with a pinch of the turmeric and salt and set aside for 10 minutes; squeeze the soaked tamarind and keep the liquid, discarding the fibers.
Heat the coconut oil in a wide clay pot or heavy pan over medium heat, add the mustard seeds and fenugreek seeds and let the mustard seeds pop.
Add the shallots, ginger, garlic, green chilies and curry leaves and fry for 6-8 minutes until the shallots turn golden.
Lower the heat, stir in the chili powder, coriander and remaining turmeric with a splash of water and cook for 1 minute without burning.
Add the tomatoes and cook for 5 minutes until soft, then pour in the tamarind liquid, the water and the salt and simmer for 5 minutes.
Slide in the fish in one layer, cover and simmer gently for 8-10 minutes, shaking the pan instead of stirring so the fish stays whole.
Pour in the coconut milk, heat for 3-4 minutes without boiling, rest for 30 minutes off the heat and serve with steamed rice.