Melt the ghee in a saucepan and fry the fish over medium flame for 1 minute on each side; set it aside in a plate.
Fry the onion and garlic until it is browned and soft; add the cumin, turmeric, coriander and pepper and fry them for 1 minute.
Add the water along to the tomato puree and simmer for 3 minutes; add the fish and continue cooking for 2 minutes on each side.
Add coriander and serve with cooked rice.