If you find yourself starving while spending time in the wilderness, hopefully you are near a body of water and have some paracord on hand. To find a solution to your hunger pains, start taking that paracord apart and pulling out the interior twine. If you are carrying 550 paracord, you should have seven interior twines. Different versions of paracord have more or less twine, possibly even none at all, but 550 is most common so you should have seven strands of twine on which you can rely.
Once you have removed the twine from your paracord shell, it is time to start tying. The goal here is a gill net, which will trap fish to feed you. Ideally you will be near a stream with a current as that will help force fish to move through the net, but it will work in other bodies of water as well, although the time it takes to catch a fish can vary depending on where you use it.
The way a gill net works is when a curious fish starts to slip through the holes and has a change of heart, trying to retreat, the strands of twine slip up behind the gill cover, trapping the fish. Larger fish may also get trapped in the holes if they are too big to pass through. Getting caught by teeth or fins is also possible. Be sure to monitor your net and retrieve fish frequently; nature will provide, but it is up to you to keep it humane. It is also your responsibility to stay within your local laws as gill netting is not legal in all areas.
To begin making your gill net, once you have removed your core, take the paracord casing and string it between two trees. This will be the top suspension line from which your netting will hang. Take your twine and start tying them to the suspension line. You can do this easily by folding in half to create a loop and placing the loop atop the top line then pulling the body of the twine through the loop in a knot called a girth hitch. Once you have attached several strands, begin with your mesh. Simply join twine from one girth hitch to another by a standard overhand knot (tie your first twine to the second, the third to the fourth, and so on). You want to keep in mind the probable size of your fishing area as you create a mesh, both in making appropriate sized holes for native fish in the area as well as the width of the net in comparison to where it will be used (size of pond/stream). Continue tying twine from opposite strands until you run out of twine or are satisfied with the size of your net, then string it across the waterway and secure it.
Once you have done the work of creating your gill net, the net will do the rest of the work for you. Gather wood for a fire over which to cook your fish or possibly take a nap while the fish magic happens. Then simply wait while the fish come to you, and enjoy them once they do.