There is a spot between the eyes and the the mouth that is in the very center of the head, if you insert a small wire ,like a straightend coat hanger into this soft spot and slide it straight back towards the spine the fish will quiver and twitch just a tiny bit! as soon as you remove the wire he will never move again? Not sure if it parilizes or kills them but it does work! Had a old timer show me this after my buddie got back from ER getting stitches from a fillet knife wound!
This is super fast and easy when you figure out the spot