In a shallow dish, mix the all-purpose flour with a pinch of salt and pepper. Dredge the white fish pieces in the flour mixture, shaking off any excess.
Heat vegetable oil in a large skillet over medium-high heat. Add the coated fish pieces and cook for about 2-3 minutes per side until they are lightly browned and cooked through. Remove the fish from the skillet and set it aside.
In the skillet, add vegetable oil. Saute the minced garlic and grated ginger for about 30 seconds until fragrant. Add the diced bell peppers and sliced onions, and cook for 2-3 minutes until they start to soften.
In a small bowl, whisk together the ketchup, rice vinegar, soy sauce, honey, and ginger until well combined. Pour the sauce mixture into the skillet with the vegetables. Stir everything together and let it simmer for 2-3 minutes until the sauce thickens slightly.
Return the cooked fish to the skillet and gently toss it in the sweet and sour sauce until it's well coated.
Serve the white fish in sweet and sour sauce over steamed rice or noodles. Garnish with sliced green onions or chopped cilantro if desired. Enjoy!