Some Like It Hot!

Lake Natron in Tanzania is famous as an important habitat for flamingos and therefore as a spectacular area for bird watching. Known as a "soda lake", the water is full of hot, alkaline springs and is very shallow, having a maximum depth of only 2 metres. As a result, the water conditions here are extreme, with a very high level of salts, a pH of 9-10, and temperatures that sometimes reach as high 48.9 degrees Celsius.

Short of the surface of the moon or the middle of the Sahara, then, it's hard to imagine a place that could be more inhospitable to fish. Yet Lake Natron is nevertheless home to a true wonder of nature - the Natron Tilapia (Alcolapia alcalicus), also appropriately known as the "Soda Cichlid".

This amazing fish has developed a number of physiological adaptations to help it survive and even thrive despite its extreme environment. For example, the high alkalinity of the lake means that excreting ammonia as waste (as most fish do) is very difficult, so the Soda Cichlid instead excretes urea through its gills. Additionally, the fish will periodically gulp air from the surface because the highly saline water of Lake Natron can quickly become oxygen deprived, especially if there are lots of fish living in a small pool. 

Therefore the fish have adapted to be able to breathe atmospheric air when necessary.

Alcolapia alcalicus is currently quite rare in the hobby, although they can be imported into the UK. Those aquarists lucky enough to find them will be happy to know that they can be acclimatised to more 'normal' aquarium conditions, but the pH should not be allowed to drop below 8.0 and the temperature should be kept at a minimum of 28°C.