Fresh water tropical aquarium fish are generally small and only live a couple/few years. I have a 30 gallon tank, so there are about 2 dozen small fish in it (mostly tiger barbs, cherry barbs, and serpa tetra). So it is no great surprise to me to see a dead one every so often. Yesterday, I noticed that the male dwarf gourami of my pair had died and was lying in a corner of the aquarium. I knew I would have to get it out soon but I was a bit busy.
What surprised me was that the female was within a couple of inches of the dead male each time I passed by. I glanced at the spot each time I passed for a couple of hours and she was always right there! So I just watched her.
Pretty impressive for a "just a fish".