Goodness, I never knew goldfish were so sensitive. I always thought they were a very hardy fish.
In the novel Lucifer's Hammer goldfish who had escaped into the wild after the destruction of human civilization grew big and fat... lots of food and no predators...
But that was just a science fiction novel, not serious literature...
They are hardier than the tropical fish that I have... so relatively speaking they are hardy. At least goldfish can be at room temperature... mine need to be between about 80-85 degrees and have have a filter and aeration system. Their room is clean now.
