People in Japan have eaten eel for thousands of years. Unagi, or freshwater Japanese eel, can cost more than bluefin tuna. But it isn't caught as adults. Instead, young eels are raised on farms. It can take 6 to 12 months of work before eels are big enough to be sold. And cooking it is just as challenging. Properly cooking Japanese eel can take years to master. When it's prepared in the kabayaki style it can cost over $90. Despite the price of eel, demand remains high. But the global catch of Japanese eel has declined by more than 75% since 1980, so prices can vary widely each year. In January 2018, young eels, also called glass eels, cost around $35,000 per kilogram.