Pour the coconut milk in a wide cooking pot. Let it boil.

Add the garlic, ginger, onion, fish sauce, and ground black pepper. Stir. Cover and cook for 5 minutes.

Arrange the fish in the cooking pot along with the Serrano pepper. Cover and then continue cooking in medium heat for 30 minutes.

Remove the cover. Let the sauce reduce to about 1/2 to 3/4 cups.

Transfer to a serving plate. Serve with warm rice.

Share and enjoy!