Peel and finely dice the garlic and onions. Clean, wash and cut the peppers into fine strips. Heat oil in a pan, add garlic and onions and fry until translucent.
Deglaze with tomatoes, bring to the boil, add paprika and cook for 2-3 minutes while stirring. Add bay leaf and oregano, season with salt and pepper. Cover and simmer for 8-10 minutes at medium heat.
In the meantime, chop some olives. Add olives and capers and cook for another 5-7 minutes. Season again with salt and pepper. Wash the fish fillets, dab dry and season with salt and pepper. Heat butter in a pan and fry fish for about 2 minutes on each side.
Place the fish in a greased ovenproof dish, spread the sauce over it. Cover with aluminium foil and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 30 minutes. Remove and garnish with oregano and jalapeños.
It goes well with rice.