At this point the fish resembles a boat's sail. Using roots or other natural cordage, tie the top of the split stick with 2 half hitches or a clove hitch to secure and tighten the panissed fish in place.
Roasting a fish in this manner is very easy, you simply angle the fish toward your fire and its done cooking when its golden brown. Cooking this way is simple, delicious, and adds absolutely no weight to your pack.
...Life becomes a little more enjoyable when little sticks at your camp, comprise your cooking equipment.