Spread the fish fillets on 4 sufficiently large pieces of aluminum foil, sprinkled with oil, season with salt, pepper, rub in with half a crushed clove of garlic and drizzle again with a little olive oil. Squeeze half a lemon over each of the fish fillets and sprinkle the fish with chopped parsley. Cut the tomatoes into slices and spread them on the fish, crumble the feta over the tomatoes and sprinkle everything with thyme.
Fold the aluminum foil up like a packet. Place the fish parcels on a baking sheet in the preheated oven and bake for about 25 minutes at 175 degrees.