I really understand what you mean. . . it is so
difficult to diagnose and treat fish, and even in very clear-cut cases I always find myself second-guessing. You lost your baby, it's heartbreaking. . . I know
I'd feel the same as you, and it isn't a happy place to be. . .
Moving and medicating fish causes stress, always. And we know that stress can lead to all kinds of problems, even death - there is no denying that fact. In some cases, it is
okay to leave a fish to let nature take its course, but sometimes there are other factors to take into consideration. Your little friend did
seem to be happy enough before you began treatment, but from what I've read, bacterial infections have the potential to cause a great deal of suffering, especially once they enter the bloodstream. The issue on his tail was spreading. . . it is very possible that it was only a matter of time before he started to have very serious complications. Once his system was compromised, the chances of him surviving treatment for a cure would have been even lower.
Remember also that there are other animals to take into account here. With a bacterial infection, there comes the very
real possibility that the illness could spread, potentially bringing harm to fellow tank-mates. How much worse to lose three over one? The only other solution you could have chosen to keep everyone safe would be to move the affected fish into isolation for the remainder of his life. I don't know that this would have been better, or ultimately ended worse as the infection spread. It's all speculation now. . . but as leery as I am of medicating, I honestly think that I would have made the same choice as you.
You care well for the creatures under your care, I love that about you. Be sad for a life lost, I'm sad, too. . . but please, John - don't blame yourself
. You didn't
do anything wrong by trying to help him heal. . .