It can go both ways, certainly, and a lot depends on the LFS and the quality of the fish they bring in, and the quality of care thereafter. My results are drastically opposite. From my LFS, I've had exactly one death, and that was a fish that was not feeding and returned because it never fed. I though I'd try to rescue it, to no avail. That probably puts the DOA rate from my LFS around 1% or less. OTOH, when I did buy fish online, which I haven't done seriously for quite some time with the exception of one fish (DOA in 24 hours, I should learn my lesson, right), about 3 or 4 years ago, the mortality rate within the first few days was horrendous, and the DOA rate was no better. Counting "replacements" for "guaranteed" fish, the mortality was greater than 60%. Some fish actually shipped with various maladies, including fungus growth in place of a missing pectoral fin in one case. The only online fish vendor I had good experiences with was The Marine Center, but they cater mostly to rarities.