Minnows make good bait for catching other fish or animals and they can be a source of food themselves in a survival situation. When trying to live off the land free time is not often something you will have plenty of. So, traps of all kinds are a huge help as they work even when you are sleeping or doing something else productive.
Here I will teach you how to build a simple minnow trap out of old discarded two liter bottles. All you will need is a couple of two liter bottles and a knife of some sort. Of course this design can be made with other materials as well. Sticks, cloth, metal, screen material and others will all work.
First step is to cut the top from one of the bottles a few inches below the cap. Cut it after it has reached its max diameter, remove the cap.
Step two is to take the second two liter bottle and cut if off near the base. Put the cap on this bottle.
Step three is to push the top of the first bottle into the second bottle. Both of the bottles should be oriented in the same direction.
Now you need some way of securing the two bottles together. String is a great way to do this by simply punching holes in the bottles after they are together and securing with string. String however isn't required as you can also secure with wire or even by running a stick or sticks through opposite holes.
Now all you have to do is place the trap wherever you see plenty of minnows. Most minnows stay near the top of the water so completely submerging the trap will not be as effective. Submerge it so that it is mostly covered by water but not completely.
How the trap works: The minnows will swim into the trap and if you are lucky they will go through the open first bottles top and become trapped. There is nothing physically required that keeps the minnows from swimming right back out the way they came. But fish aren't very bright. They swim around in the trap and can't figure out how to get back out.
The first top funnels them to the narrow opening but once inside the opening doesn't reside against the side and the corners which is where they will be directed as they swim against the sides. Only rarely will one make it back out the way it came in.
To remove the minnows simply unscrew the red cap.
There you have it, a simple minnow trap.
This is the most basic simple trap. Now that you know how to make it and understand the ancient concept of how it works. This trap can be extrapolated into bigger more elaborate traps that rely on the same principle.