The Golden Catfish of the Desert

Here is one of the world’s rarest and strangest fish, the golden cave catfish (Clarias cavernicola) which can be found only one place on Earth, the Algamas/Dragonsbreath cave in the Namib Desert.  This incredible cavern is 100 meters (300 feet) beneath the desert and it holds the world’s largest known underground lake (discounting all subglacial lakes—which can be huge).  Above ground is an arid desert wasteland, but in cave is a huge lake where unfathomed waters may descend another 100 meters into the Earth.  Since only a narrow chasm opens to the sky, the lake has a very limited ecosystem built around whatever falls into this chasm (which was only discovered by science in 1986).  These blind ascetic catfish dwell on such scraps and on the white shrimp and strange aquatic worms which live in the water beneath the desert.  Though they have lost their eyes, their other senses have become extremely acute in order to find every bug or speck of nutrient which falls into the hidden lake.  Additionally, these small (16 cm/6 inch) fish have a limited ability to sip air–so that they can better survive the still and anaerobic depths of their hidden lake. The entire species may only consist of a few hundred (or thousand) individuals.

 

Advertisement

The African Sharptooth Catfish

Here is a stamp which combines two of my fascinations—catfish and Namibia.  Of course Namibia is a vast and profoundly arid desert—literally a sea of sand—so perhaps you are wondering how a catfish made it onto their postage.  Well the African sharptooth catfish (Clarias gariepinus) has a habit of getting everywhere.  It lives throughout most of Africa and the Middle East and (though ill-conceived aquaculture) has established colonies in Vietnam, India, Brazil, and Indonesia.  The catfish is an air breather.  It can sip pure air without the use of its gills, so it can survive in puddles, mud wallows, and even in filthy anaerobic water.  Some of them have moved into the sewers of big cities.  Speaking of big it is arguably Africa’s largest catfish with an average adult length of 1–1.5 m (3 ft 3 inches –4 ft 11 inches).  Even in a dry land like Namibia this tough persistent catfish manages to find watercourses of one sort or another.  Like its close cousin, the walking catfish of Asia, the African sharptooth catfish is a remarkable creature.

African sharptooth catfish (C. gariepinus)