Juvenile Natal knifejaw Oplegnathus robinsoni at A-Frame.
Photo Dieter Stegemann
Juvenile Cape knifejaw Oplegnathus conwayi
Photo Guido Zsilavecz.
Dieter Stegemann photographed this fish at A-Frame, and first thought it was a Cape knifejaw, but when looking at the photo in more detail realized it was actually the young of the Natal knifejaw. The difference between them is not obvious at first glance, as both are yellow with black bars, but while the Cape knifejaw has only two bars (with at most a hint of a third one on occasions), the Natal knifejaw has five. The Natal knifejaw also has a much sharper snout and the posterior dorsal and anal fin are also more pointed.
The normal range of the Natal knifejaw is Mozambique and Natal, with juveniles ranging further south, to Tsitsikamma. It is likely that this fish was brought down by the Agulhas current, and it is unlikely that it will survive in Cape Towns colder waters.
Coastal fishes of the Cape Peninsula and False Bay, a divers' identification guide, G Zsilavecz, 2005.
Two Oceans, A guide to the marine life of Southern Africa, GM Branch, CL Griffiths, ML Branch and LE Beckley, 1994.
Smiths' Sea Fishes, MM Smith and PC Heemstra, 1986.
Coastal Fishes of Southern Africa, PC Heemsta and E Heemstra, 2004.
Reef Fishes and Corals. Dennis King, 1996