Barehead goby photographed in Port Elisabeth
Barehead goby photograped in Port Elisabeth. Note the blue spot on the trailing edge of the first dorsal fin.
Both photos by Johan Swanepoel
Barehead goby more from the side, again showing the spot on the dorsal fin. Do also note the pattern, and compare it with the next fish. This fish was photographed in Cape Town, at A-Frame.
Knysna sand goby. Note that the dots along the side are solid blobs, and are not constructed out of smaller spots as in the barehead goby. Note also the thin white bars between those solid blobs running across the back - these are quite vivid when seen underwater. This fish was also photographed in Cape Town, at Long Beach.
Knysna sand goby in the estuary of the Palmiet river.
Bottom three photos by Guido Zsilavecz
The barehead goby (Caffrogobius nudiceps) and Knysna sand goby (Psammogobius knysnaensis) are very easy to confuse, in that both are pale with dark speckles, and both are found on sand. In Cape Town the barehead goby is found at about every shore dive site - it is rare not to see any on a dive. Because they are so common the Knysna sand goby, which is much less commonly seen, actually stands out. One of the reasons is that it has narrow white bands along the back which stand out from the slightly off-white body and sand. Furthermore, the dark blobs along the back are quite prominent; much more than those spots on the barehead goby.
The barehead goby has a range which extends further west than that of the Knysna sand goby, ranging from East London to Walvis Bay, while the Knysna sand goby reaches further east; from Port Nolloth to KwaZulu-Natal. They thus overlap over most of their range, and both are found in both marine and estuarine environments.
Coastal Fishes of the Cape Peninsula and False Bay, A Diver' Identification Guide, G. Zsilavecz, 2005
Biology and Ecology of Fishes in Southern African Estuaries, AK Whitfield, 1998
Two Oceans, A guide to the marine life of Southern Africa, GM Branch, CL Griffiths, ML Branch and LE Beckley, 1994.