Sharptooth Catfish

During a visit in November to Rietvlei Nature Reserve on Pretoria’s outskirts, along with friend and colleague Hannes Rossouw, we were treated to the show of hundreds of Sharptooth Catfish trying to move upstream following a good downpour the day before. What an amazing spectacle it was!

Sharptooth Catfish moving upstream in the Rietvlei Nature Reserve

The reason why they’re moving upstream is to mate and lay eggs in newly inundated areas. These catfish were videoed at the Marais Dam in the reserve, vying for mating rights and the best spots to lay and fertilise their eggs.

Remember that I am available to escort you on a guided tour of the Rietvlei Nature Reserve when you visit Pretoria, and that Hannes will gladly accompany us if you’re looking for tips from an expert wildlife photography tutor!

Clarias gariepinus

Distributed naturally over almost all of sub-Saharan Africa and in a few river systems in the Middle East as well, the Sharptooth Catfish is a most adaptable species capable of living in almost any freshwater habitat; adapting even to life in sewerage treatment works or very muddy, drying pools. This is thanks to their ability to breathe air directly and their ability to travel across dry ground, especially in wet weather.

One of the biggest freshwater fish in Africa, Sharptooth Catfish may grow to 1.7m in length and weigh up to 60kg. They’re omnivores and will feed on anything living or dead that will fit in their sizable mouths. In turn they fall victim to many predatory birds, mammals and crocodiles.

Sharptooth Catfish spawn in seasonally inundated areas surrounding their home waters, usually at night following good rains. Males become involved in serious fights for dominance and the right to mate with females. Females are very fertile – even a catfish weighing only 2kg can produce 45,000 eggs! The eggs hatch within 1-3 days of being laid, and the fry develop exceptionally quickly. There is no maternal care for the eggs or newly hatched fry – in fact, cannibalism is very common in this species.

The IUCN lists the Sharptooth Catfish as being of least concern. – it is probably the most widely distributed fish species on the continent of Africa. It is a popular aquaculture species (especially in poorer communities) and has been introduced in various other parts of the world, where escaped populations are a serious danger to indigenous fish and other water-living creatures. In South Africa they occur naturally in all provinces except the Eastern and Western Cape, though they have invaded freshwater systems in these provinces as well thanks to water transfer schemes and stocking by farmers and anglers.