The problem you have there sadly is the stress factor , this is where I wish we fish keepers all lived in the same place so I could pop over and show you how easy it is to do Turtlemommy decided to give it a go nd found it an easy thing to do and was glad she did it because now she can do it again but basically its add the oil of cloves to the water mix it in well and place your koi into the mix , the koi will go over onto its side and will gradually loose conciousness after about 5 mins if not simply add another 5-10 ml of oil of cloves checking the fish from time to time , your looking for no movement of the tail once thats happened pick the fish out and treat as per my post , once the wound has been treated with malachite and propolis which I can assure you you can buy from the same health food store as the oil of cloves , simply place the koi cupped in your hands back into the water in a flow of water with air going through it .
The whole operation is done in less than five minutes, the fish wont feel a thing .
If you ever wish to euthanize a koi to save its suffering you simply leave it in the solution of oil of cloves where it will peacefully pass away
Dave
