Cyanide is a tool used by a small amount of collectors to catch fish. The cyanide stuns the fish, making them much easier to catch. But cyanide also has a lot of negative effects. For one, it injures the fish. Research shows that most cyanide-caught fish die within 48 hours of being caught. In addition to fish death, corals are also very sensitive to cyanide. It can be somewhat hard to find out which stores order cyanide exposed livestock, but ask your favorite LFS who they purchase livestock from and research the company. Chances are, someone out there has information on the wholesaler in question.