Dead, dead, dead

The three koi I had in a man-made pond died last week. 
It was partly my fault. Although the leg amputation in February and shoulder replacement in May have made getting out to see the pond risky because I'm using a wheelchair and there are two tricky steps involved, I had made the trip and could have kept doing so. If I had, I'd have seen that the power to their water and air pump was out. A friend fed them on Sunday, they were dead on Wednesday. The friend says he thinks the pumps were going, but I doubt that; the fish have survived much longer power outages, even in summer, when working pumps are essential (warm water holds less oxygen than cold water). I should have specifically asked him to check to see if the little waterfall was flowing. 

Other than things you can't see and some aquatic plants, this is empty.

I also blame the gardeners my brothers hired to clean up the grounds (I admit I was slow to do this, which is why they stepped in and hired people without telling me, but I had planned to make a call that week). They uncovered the outlet to the devices and didn't put the cover back. There was a short but strong storm that Sunday that may have shorted out the power. Also, there was a sheen of oil on the water, which would have blocked oxygen, and I suspect it was runoff from the mulch they used around the pond. 
One of the fish was twenty-five years old and had been around when my parents were alive. The other two I'd bought five years ago. All three had many more years ahead of them. I'd named the three after my brothers and I. It's stupid to give pets names; it makes it harder when they die.
The way the fish died would have been unpleasant. It is a precursor to the way I'll probably die when the form of cancer that required removal of my leg spreads to my lungs. 
They will be my last pets. Ever. I can't have pets because I love them too much and they always die, saddening me for years. The joy they give when alive doesn't outweigh the misery. Once the sadness I feel now ebbs a little, it will be almost nice not to have to worry about anything other than a couple of houseplants. But that ebbing won't be for years, and I probably don't have that long.