Post like this is tough not to offend someone. I personally would never kill a animal that I brought to my yard, directly or in directly due to the pond, fruit trees, pets etc. I feel it is the humans responsibility to take the proper action on there property so killing of a animal doing its thing does not happen. I personally do not like excuses like the fence is to much money, that should have been thought about before ponds, fruit trees etc., were put on a property. Many people use that excuse that it is cheaper just to kill the problem then to fix the problem, while true it is a poor excuse. You stated your pond can't be seen from the house, so you made a very private watering hole for visitors, so the chance you walking up on something again is very high. In my opinion you should where a bell or make noise of some sort every time you go out there. Most animals do not just attack or kill humans for no good reason, most of the time the humans are at fault. I photograph all sorts of wildlife (have for years) and with that said respect still has to been given on every outing. I never needed bear spray but buy it every time we photograph bears just in case. From my experiences most wildlife do not attack first and ask questions later like humans do. They give many warning signs first, like a simple ear positioning ( moose are good for this). It would help if you learn defensive signs also of the animals in your area also. From my experience most people really do not know when they are being attacked, most of the time they are mock charges. I will still scare the heck out of you for sure but does not warrant killing of the animal. Maybe in your case it was different with rabies etc, I was not there. Moving forward I would make your place more wild animal safe, more so if you are a rescue.