In May 1851, explorers Charles John Andersson and Francis Galton stumbled across the unusual Lake Otjikoto. The name of the lake is Herero for 'deep hole', and its waters fill a limestone sinkhole measuring 100m by 150m, reaching depths of 55m. Interestingly, Lake Otjikoto and nearby Lake Guinas are the only natural lakes in Namibia, and they’re also the only known habitats of the unusual mouth-brooding cichlid fish.
These fish are psychedelic in appearance – ranging from dark green to bright red, yellow and blue – and are believed by biologists to eschew camouflage due to the absence of predators in this isolated environment. It’s thought that these fish evolved from tilapia (bream) washed into the lake by ancient floods.
In 1915, the retreating German army dumped weaponry and ammunition into the lake to prevent it from falling into South African hands. It’s rumoured that they jettisoned five cannons, 10 cannon bases, three Gatling guns and between 300 and 400 wagonloads of ammunition. Some of this stuff was salvaged in 1916 at great cost and effort by the South African army, the Tsumeb Corporation and the National Museum of Namibia. In 1970, divers discovered a Krupp ammunition wagon 41m below the surface; it’s on display at the Owela Museum in Windhoek. In 1977 and 1983, two more ammunition carriers were salvaged as well as a large cannon, and are now on display at the Tsumeb Mining Museum.
Although the site is undeveloped, there is a ticket booth, an adjacent car park and several small kiosks selling cold drinks and small snacks, as well as quite a bit of shade. While treasure seekers have been known to don scuba gear and search the lake under cover of night, diving (and swimming for that matter) is presently forbidden.
Lake Otjikoto lies 25km north of Tsumeb along the B1, and there are signs marking the turn-off. Note that the entry to the lake is just past the sign for it (about 100m) coming from Etosha.