This species of fish is actually close to being considered extinct, which only drives the price for this funky looking fish’s organ. The Chinese believe that this guy’s bladder is rich in collagen, helping smooth human skin and used in skin treatments all over the world. It also has been used to help joint pains, as well as several bone applications and treatments. Oddly enough, this fish has another use, quite another use indeed. In Mexico, they use these fish bladders to transport large amounts of cocaine.
The fish you mean is the ‘totoaba’ – Cynoscion macdonaldi, the Mexican giant croaker.
The Chinese are hardly the only culprits in the decimation of the totoaba. While the Chinese prize their recipe for Seen Kow (a rare, regal, expensive soup-stock), which is made from the totoaba’s ‘buche’ (air bladder), through the 1960s, southern Californians ran through huge quantities ‘Totuava Filet’ packets that were sold openly in the supermarkets, oblivious to the industrial-scale slaughter of the giant fish 150-miles away in the northern Sea of Cortez.