A couple days ago as I started misc tasks around the house, one of my trips past the fish tank I noticed all the Koi had died during the night.
I have had fish die before, but never so many so suddenly; and obviously, the buck had to stop with me, since there is no one else taking responsibility. I like to be casual with my projects, expecting everything to work out without getting too anal retentive about things, but I need to remember there are some things that need scrupulous care, and my normal “it can wait” attitude needs a little adjustment with some things, especially living systems that depend on artificial support.
Perhaps the issue will turn out to be some rare disease that I had no control over, but right now I’m operating under the assumption that the issue was warming water with warming temps in the greenhouse, and an algae bloom that consumed all the oxygen overnight. Something I was well aware of in theory, but really didn’t understand the practical implications.
The day before everything seemed fine, but I had noticed some murkiness to the water. The fish were doing their normal feeding, competing at the surface for the pellets as I dropped them in the water. The sudden deaths took me completely by surprise, and the shock was even greater when I started looking at replacements on ebay. The money loss was likely in the neighborhood of a couple hundred dollars.
And it all could have been avoided if I had just a little more experience and/or caution. I believe a water replacement of about 1/3 the day before would have avoided the disaster. An air pump would have avoided the disaster. A better filter would have avoided the disaster.
The fact is I got complacent and didn’t do everything I could have done to ensure their survival, and the only consolation is that these are still early days in my fish raising adventures, so I at least will have this failure to learn from. Going into the more expensive Koi I will be inspired to be more serious in protecting them.