Long term Koi fish died
Question:
This weekend I found my two koi dead. They were the only koi I have. Visibly there are no signs of injury or disease. The other fish, goldfish, are still alive. Any idea as to why the koi died. They’ve been in my pond for several years and I don’t think I did anything different this year than in the past in winterizing my pond.
Answer:
The death of your Koi was probably due to lack of oxygen or a severe and fast water temperature change. Although everything was done the same as in previous years, your Koi have grown larger and their oxygen needs would have been correspondingly greater. It is best to add an air pump to ponds containing Koi.