After a heavy rainfall with thunderstorms, all my 7 Kois suddenly died . All had different sizes and ages, without previous signs of disease for at least 2 years. :crybaby:

Oxygen, ammonia, all NHx, pH and Hardness levels where in the normal range, even though a lot of rainwater fell inside my +100 gallon pond. Nearby contaminants? None that I could have seen or imagine of.

Since there where many nearby lightning strikes on the electric power lines (with power failure) , I suspect that some kind of current might have electrocuted my Kois through the water pump or UV filter.

Could this happen? Any opinions ? Similar cases?

I would really appreciate some opinions on what could have happened to my Kois, so I could try to avoid it before I start over again.

Thanks

Henning