For the past 12 years, London Zoo has been breeding a rare fish with crucial help from a large commercial manufacturer. British Gypsum supplies the zoo with gypsum, a mineral it mines in Brightling, southeast England.
Gypsum is normally used as a fertilizer and in building products, but in this case it’s the only way of keep the mineral balance of the water just right for the peculiar needs of the checkered pupfish.
London Zoo runs conservation programs in more than 50 countries that are crucial to the survival of several thousand species, but the checkered pupfish has been particularly tricky. It only exists in one Mexican state, San Luis Potosí, and mostly in a single lake called Media Luna. The fish’s environment is being threatened by agriculture, tourism, and invasive species. And Mexico has no government-led conservation program to protect it.