This entry will be short and not so sweet. This is a common occurrence in the koi world. It must be extremely common because soon after encountering this, the most common statement is:
We've all done that.
Mine happened a couple of days after purchasing some tosai from a local dealer. I acquired two beni kumonryu to grow out and observe their changeover time; I looked at this buy as a learning experience. I didn't realize that I'd be learning another, far more stinging, lesson.
So the fish were brought home, floated for 15 minutes in my side 500-gallon tank, and released into their new home. I had placed two other of my smaller fish in the tank as canaries and tank mates.
Two days later, while looking over my new fish, I noticed the water level was just a little low. I placed the garden hose to spray over the top of the tank. That way the chlorine in the city water was assisted in gassing away. I went inside and went about doing some minor chores for just a few minutes, then return.
When I returned from the big box store, my wife asked me:
Do you have water running?
You know those scenes from the movies; where your life flashes before your eyes. Well in this case, it was the life of two beni kumonryus, one chagoi, and a sanke. I raced outside, only to confirm my worst fears; four koi expired; chloride poisoning. Why didn't I pick up that kitchen timer? Why did I walk away? Who's in charge to allow me to have koi? What will the koi club people say when I verbally relive this? They said:
We've all done that.