Place a layer of potatoes in a large frying pan, top with a layer of onions then garlic. Sprinkle with salt, pepper, thyme, bay leaves, oil and vinegar. Add enough water to cover. Bring to a boil and simmer for 10 minutes. Add fish and enough water to cover. Sprinkle fish with salt. Cover and simmer for 10 minutes. Pour off any remaining liquid. Sprinkle with paprika and serve.