| First of all, I'm very sorry for your loss. It will hurt for a while but I hope you are able to get back on the horse after some time has passed. And I'm sure you don't want to hear this right now but it is important to know why this happened so that you can learn from this painful lessons and add it to your experience memory bank. Unfortunately, this is how many of us learned koi keeping- one problem at a time.
It sure does sound like a pH crash. But you said you tested the water and it was fine? What was the pH when you tested. And what was the ammonia and the nitrate? What was the water temperature?
How many fish did you have and what is the size of pond? What type of filters do you have? When was the last water change and do you use a prefilter on water entering your pond? JR |