Place the fish fillets in a dish, pour the lemon juice and garlic. Leave to marinate while you prepare the other ingredients.
Seed the tomatoes and peppers and cut them into strips. Slice the onion thinly.
In the saucepan heat a drizzle of olive oil. Fry the onion for 1 to 2 minutes. Add the tomatoes and peppers. Fry for 5 minutes.
Add the fish fillets and cover with coconut milk.
Add palm oil and coriander, and season with salt and pepper. Simmer for 10 to 15 minutes, until the fish is cooked. Serve with fresh coriander.