In order for the fish to bake in short time and the tomato juices to reduce and form a nice sauce, you should pick a big pan and not overcrowd the vegetables.
Salt and pepper the fish and place it in the pan. Sprinkle it with some of the oregano.
In a bowl, mix all the rest of the ingredients except olive oil. Add again some salt and pepper and transfer to the pan.
Drizzle with olive oil.
Bake for about 20-25 minutes, or until the fish flakes easily with a fork.
Serve with slices of lemon and a nice sourdough bread.
Notes
The fish should be about 1 inch thick, cut in slices.You can also use fish fillets, but depending on their size cooking time can be 5 minutes longer or shorter.Choose your favorite fish. Some suggestions are: tilapia, halibut, cod, bass, grouper, school shark