grass snakes and fish

Question
Hi,This afternoon I spotted a Ghost Koi floating in my pond with a small grass snake (head about the size of a thumb nail)attached by its mouth to the Kois fin, On inspecting the Koi which was about 10in long, I could see nothing wrong that might have caused its death. I had noticed the other two Koi had been mating and were all over the pond. My question is, could the small snake have killed a Koi of this size? or could the other Koi have damaged it in their mating frenzy?. It was very happy and healthy yesterday. The pond is 30ft x 15 and supports newts and until the 2 or 3 grass snakes appeared a lot of frogs!. I would appreciate your views on this matter as I hate to see the fish die for no apparent reason. Thanks in advance. Dorothy

Answer
Hi,
I wouldn't think that the grass snake had killed your koi,but stranger things have happened,and on very rare occasions when spawning a koi could die from being constantly chased and harried by the males, but it is unlikely and most probably died from natural causes, coincidently while the koi where chasing.
Sorry that I cannot be more specific but without seeing the koi it is really impossible to say the cause of death.
George.