Heat the oil, then add the onion and garlic and fry them lightly but do not brown.
Add the curry powder, stir and cook for 3 to 4 minutes. Add water or coconut milk,
lime juice and mango, and cook until thick. Put in fish and cook gently until tender.
Do not stir fish, but prevent it from sticking to the bottom of the pan, the pan
may be moved gently backward and forward.