Heat the oil in a wide saucepan over a medium heat. Add the curry powder and stir-fry for 20–30 seconds or until fragrant. Add the monkfish, coriander and red onion and cook, stirring, for a further 20–30 seconds.
Add the lime rind and juice and the coconut milk. Bring to the boil, reduce the heat and simmer for 15 minutes or until the fish is cooked through. Season to taste and serve immediately with steamed rice.