Koi help!

[Bethfleming]

At my place of employment (large skilled nursing facility) we have a koi/gold fish pond. We had been doing great all year, even survived a frigid Iowa winter, and after adding water on Friday, my staff called to say all the fish died. I did add the dechlorinator, so I am at a loss of what the heck happened. Myself and my residents (who had come to love these large pets) are devastated. Any ideas or suggestions on how to start over? I am terrible at guessing water quantity but maybe 1500 gallon? I can post photos tomorrow when I am back at work. TIA!

 

[Meadowlark]

I would guess the likely cause to be ph shock from the new water (which was also likely at a different temp than the existing).

Summer temps fish are super sensitive to ph and/or temp changes changes. If you can, test the ph of the new water vs old water...and before restocking be sure everything is stable.

 

[JRS]

Welcome to the forum, sorry to hear about your fish. How many did you lose?

First time you added water this year or a normal routine? How much was added? Some utilities use chloramine instead of chorine which requires appropriate water conditioner; although many treatments handle both.

KH may also be a factor. Low KH water is not buffered well, allowing large pH swings. Elevated levels of ammonia and nitrite can be a factor also; should be at zero in a healthy pond. The toxicity of ammonia compounds is also related to pH so perhaps the balance was tipped if the pH suddenly rose.

 

[j.w]

@Bethfleming
Sorry to meet on this sad note and hope someone here can help you figure out what exactly happened. Testing your water in all area's might help. Get a good liquid type tester if you don't have one already. Find out for sure from you water company exactly what chems they are putting in the water now. Maybe something new is being added?