We take both olive oil and peanut oil on our trips.  Peanut oil holds up better to higher heat and so we use that more often when frying fish.  But we don't bathe the fish in it or deepfry, we just use enough to keep the fish from sticking and cook it evenly.  In a 7 day trip, we probably go through less 6 oz of each kind.  We use the olive oil for other foods that require oil to prepare, and for frying things on lower heat - like pancakes.