In a small bowl. Combine water, tomato sauce,sugar, soy sauce, vinegar, salt and pepper. Stir until sugar and salt are dissolved. Set aside
In a pan over medium heat, heat about 1 tablespoon oil. Saute onion, ginger, and garlic until translucent. Add the pre-mix sauce you just made and let simmer for 3-4 minutes. Taste and adjust according to your preference.
Add the sliced green and red bell peppers and simmer again until vegetables are softer/tender. Add the cornstarch diluted in water gradually until desired thickness of the sauce is reached.
Add fried fish fillets and tofu and cook, tossing gently, for about 1 to 2 minutes or until heated through and coated with sauce. Bon Appetit!