I was browsing books at the library and came across ...
"The Lizard King : The True Crimes and Passions of the World's Greatest Reptile Smugglers" by Bryan Christy
This is an amazing book detailing the rampant, out-of-control world of reptile smuggling, and details a couple od cases of tropical fish smuggling as well, but really shows how most of the animals you see in your local pet store are obtained. Pretty enthralling, scary reading. It will make you think twice before your next purchase.
I know a lot of fish enthusiasts are also lovers of other pets, so I thought you may want to check it out.