Combine vinegar, garlic paste, and ginger paste, and marinate the fish fillets with this mixture for 15–20 minutes.
In a separate bowl, mix orange juice, soy sauce, tomato ketchup, honey, and gochujang sauce to create a spicy, tangy sauce.
Lightly coat the marinated fish pieces with cornflour, all purpose flour and rice flour.
Deep fry the coated fish pieces until golden brown and crispy. Set aside.
In the same pan, heat a little oil and sauté the sliced onions, bell pepper, garlic, and green chilies until they soften and become fragrant (about 3–4 minutes).
Add the prepared sauce mixture to the sautéed vegetables and cook for another 2-3 minutes until it thickens slightly.
Toss the fried fish into the sauce and vegetables, stirring gently to coat the pieces evenly.
Garnish with chopped spring onions and serve hot.