Wash the fish fillets, pat dry, and cut into portion-sized pieces. Sprinkle with salt, chili powder, and 1 tsp thyme. Peel and finely chop the onion and garlic. Halve, core, and wash the peppers. Roughly chop and puree one green pepper. Cut the other peppers into bite-sized pieces.
Heat the oil in a frying pan and fry the fish fillets over medium heat for 3 minutes each side. Put the fish into a baking dish, cover, and keep warm in the oven at 80°C. Put the onion, garlic, and chopped peppers into the same pan and fry gently in the remaining frying fat for about 5 minutes, stirring. Add the wine. Add 1 tsp thyme and season with salt and pepper. Simmer for about 5 minutes, until the liquid has almost all evaporated. Carefully stir in the pureed pepper and heat through. Take the fish fillets out of the oven and serve on warmed plates with the peppers. Serve garnished with herbs.