Why Did My Koi Suddenly Die?

The most common reason for a koi to suddenly die is low oxygen levels in the pond. These low oxygen issues usually come from certain weather conditions and pond features. One clear sign of low oxygen is fish gasping at the water’s surface, often seen in the early morning. We would always recommend using an air pump to oxygenate you pond continually, Other common causes include poor water quality. We recommend testing your water regularly with a water test kit like the NT Labs Pond Multi Test Kit to prevent koi deaths. Another main cause could be parasites. If you think parasites are on your fish, we suggest doing a koi skin scrape.