I have recently changed LFS because of what you are all discussing.
I suspect my original LFS sold me bangaii's that were caught with Cyanide (I can't confirm this).
I confronted him and asked him why most of his fish appear sick in his tank (A lot of their fish had spots on them, swimming funny, etc...). He answered that's how it is in this hobby and that some are healthy and others are chucked away.
Finally, I asked him who his supplier is and if he can confirm that the bangaii's i bought we're captive bred. He said they were in fact wild and that the source doesn't really matter because most sources lie anyway.
That's when i decided to look elsewhere. I found an LFS that buys all their stock from Quality Marine which seems very reputable. It may be a bit more expensive but I am buying captive bred when possible and for the most part the fish are MAC certified.
I recommend anyone thinking seriously about the health of our ecosystems to consider purchasing from a MAC certified reseller or retailer (
http://www.aquariumcouncil.org/)