The major goal of this lesson is to provide students with some of the tools they will need to analyze and solve the many complex problems they will face during their lifetimes. In the lesson, students learn to use Flow Charts and Feedback Diagrams to analyze a very complex problem of ecological sustainability. The lesson looks at a specific case study—from my home town in the Philippines—of the Live Reef Fish Trade now threatening survival of the Coral Reef Triangle of Southeast Asia. Live reef fish have long been traded around Southeast Asia as a luxury food item, but in recent decades trade in fish captured on coral reefs has expanded rapidly. Although the trade has provided communities with additional income, these benefits are unsustainable and have come at considerable cost to the environment. This lesson begins by having students analyze a familiar or personal problem, using Flow Charts and Feedback Diagrams, and then moves on to the application of those tools to a complex environmental problem. The lesson could be completed in a 50-minute class session, but using it over two class sessions would be preferable. Everything needed for the lesson is downloadable from the BLOSSOMS website, including blank Flow Charts and Feedback Diagrams, as well as articles on the Philippines case study from the World Wildlife Fund and the United States Agency for International Development.