Unfortunately it's what the LFS recommended. As I'm new to the hobby I'm trying my best to read up as much information as I can and was told to try that.
I read quite a lot these last few days, went back to the store to check by myself how the rest of those fish were doing, considered the options and made the call not to treat with actual medication because I came to the conclusion that this just looked like a sad combination of multiple stress factors. Out of the 5 that I lost, only one really seemed truly affected by columnaris/saddleback, the others could've been considered as just being nipped and/or rough handled. Columnaris is said to be ALWAYS present in the water, however it will make fish sick when conditions are "right" and/or if a strong strain comes into play. I read that on some other forum/site. I think the quick removal of bodies, the melafix, the isolation in my makeshift "quarantine tank" plus the quick response with significant water changes all helped.
I'm halfway thru the melafix "treatment" and knocking on wood that once I'm done with it the fish will continue continue to thrive.
I had my doubts about treating with some of the meds suggested because my beneficial bacteria could have been wiped out and the sum of observed symptoms ultimately didn't add up to a definitive "diagnosis". I again have to say that this was much like going to a human doctor (and I've seen this a lot with myself and my son) where the doctor isn't certain and says well, do this and that and if things don't improve in a couple of days then we'll do more tests and see where things go. The reality is they can't pinpoint it and won't go with hard meds until they're sure. At that point it's your call to either seek a second opinion, agree with the wait and see option or demand to start a meds regimen, and there's really no bulletproof "right" call.
I personally am overall inclined to avoid any meds as much as possible because the list of "possible side effects" always looks like it will just make me take more meds and cause some other issues, so that was my frame of mind in tackling this.
Losing half the shoal wasn't easy, but putting my entire tank thru meds didn't seem like the right thing to do. If anything, I won't be buying any more fish until the weather here becomes a bit warmer. It became pretty obvious that all stores around me are receiving severely distressed fish at the moment.
Best of luck, this was a harsh reminder to me that these pets are by far more hands-on than most people assume, and that makes it all the more interesting.
