I remember that a few years ago when I was a child, I had a Bloodfin tetra(I'm not sure if it was this fish type, but it resembles my fish tremendously) fish I believed to be a male.
That fish lived for two years until we presumed it dead. I knew that a fish was dead when it floated to the top, but we thought it was dead because it was at the bottom of the tank for many days and still did not become active when we moved the tank, etc. We flushed the fish down the toilet ):
Out of curiosity, was that fish dead, or was it feeling unwell?
Also, we kept our fish in some sort of flower vase, but I was too naive and that was before I knew anything about fishes.