Comparing a family dog to a goldfish is such utter nonsense that you have to be a troll.
But the OPs comment was, to me at least, as absurd as if I said to someone “I don’t think you should worry so much about saving your daughter’s life. When I lost my dog, I was sad, but I got over it.”
These are not in the same category to most people, and you can’t assume your experience of losing a dog gives you insight into losing a child. Same goes with dog -> goldfish.