Turn on the oven to preheat to 200 degrees. Boil potatoes in slightly salted water for 4 minutes. Place the potatoes in a colander, let the water drain, then put the potatoes back in the pot, add 1 tablespoon of olive oil, stir and set aside.
In a large, thick-walled skillet, heat the remaining olive oil, pour the red onion, garlic, and all the bell peppers into the preheated pan, fry, stirring occasionally, for about 5 minutes.
Then put mushrooms and tomatoes in a frying pan, pour over with wine, cook, stirring occasionally, for a few minutes. Put the pieces of fish in a pan with vegetables, add olives, herbs, and spices.
Lightly grease a large ovenproof dish with vegetable oil and put the contents of the pan in it, put the potato slices on top.
Place the dish in a preheated oven and bake the dish for about 45 minutes, until the fish is cooked and the potatoes are golden brown.