Use a frying pan big enough to accommodate the trout fillets. Finely chop garlic and fry in oil over low heat for a few minutes. Then add tomatoes, finely chopped olives and anchovies, oregano and chilli powder. Bring to boil, stir well and then cook over a low heat for 10 minutes. Try to move most of sauce out of the way, lay the fillets skin side down in the pan and then spread sauce back on top of them. Again, heat up and then cook slowly until fish is done, about 7-8 minutes. Serve with rice and a green vegetable.