Carp are a common fish that can be found in ponds and lakes worldwide. How could they be endangered? It has long been believed that there was only one species in the whole world, but it turns out that Japan has 2 carp species. The discovery was made long ago by Siebold, but his findings were rejected by the academic community of his time. The mystery was finally solved with modern science. Tune in to learn more about Japan's enigmatic and endangered carp.