Wash the fish, pat dry, brush with lemon juice, salt and pepper. Heat the oil in a pan and fry the fish in it for about 1 minute on both sides and remove.
Heat some oil in it again and fry the onion and garlic in it. Add the remaining spices, deglaze with the coconut milk and a little water, bring to the boil.
Carefully put the fish in and cook on low heat for another 10 minutes. Season to taste with salt, pepper and green chilli.