Dice the bell peppers and onions into cubes. Place the chopped veggies into the bottom of a dutch oven.
In a small bowl, combine the flour, salt, and sugar. Dip each piece of fish into the flour and place it on top of the diced veggies.
In another small bowl, whisk the water, tomato sauce, ketchup, and oil together and pour it over the fish. Bake at 350°F until the sauce begins to boil.
Then turn the heat to 250°F and bake the fish for 4 hours. Eat immediately or can the fish for later. Enjoy!