Season Mahi mahi fillets with salt and pepper.
Heat the cooking oil in a frying pan.
When the oil gets hot, dredge the seasoned mahi mahi fillets in all-purpose flour. Fry each side in medium heat for 3 to 5 minutes or until medium brown. Remove the fried fish from the pan. Arrange in a serving plate. Set aside.
Meanwhile, make the sweet and sour sauce by combining vinegar, soy sauce, ketchup, and sugar in a bowl. Mix well.
Heat a saucepan and pour-in the vinegar mixture. Let boil.
Adjust the heat to medium and then add the carrots, bell peppers, and onion. Stir and cook for 2 minutes.
Pour-in the cornstarch diluted in water. Stir quickly. Continue to stir gently until the texture becomes thick.
Turn the heat off. Scoop some sweet and sour sauce and top over the fried Mahi mahi.
Serve with warm steamed white rice.
Share and enjoy!