I would say, sadly, most fishes come from Indonesia and Philippines where they are usually caught using cyanide which is the easiest way to catch. I doubt these fishermen know anything about the effect of cyanide on these fishes and damages done to their own reef environment, and the middlemen supplier prob don't care much.
The difference is probably how much the fishes got it within their bodies. Fishes caught further down the cyanide source may be spared. The rest may look ok now but many may not feed and would get thinner each day and/or fall prey to parasites/diseases. Even those that are eating would get thinner each day too. So, really depends on luck.
I understand that fishes from the caribbean, red sea, hawaii and australian shipments are less likely to be cyanide caught.