Clean and gut the fish. Make four to five deep cuts along both sides of the fish. Sprinkle lightly with salt and pepper and a little tapioca flour.
Heat enough oil in a wok until hot. Add in fish and deep-fry over a high heat for one to two minutes.
Lower the heat to medium and fry fish in the hot oil until it turns crispy and golden brown. Remove from oil and drain on crumpled kitchen paper.
Whisk all the sauce ingredients in a blender until fine and well combined. Heat 3 tbsp oil in a wok and sauté the blended ingredients over a low heat until fragrant and oil rises to the top. Add seasoning to taste and simmer for three to four minutes.
Pour the sauce over the fried fish and serve immediately with a sprinkling of finely sliced kaffir lime leaves.