Photos Guido Zsilavecz
Update!Seems like there are many individuals of this fish swimming around at Long Beach: one was sighted on 17 June, and three on 23 June, all at Long Beach.
A sighting at Long Beach of an individual of this species was reported in the News section on 30 April. Again at Long Beach another one was seen, this time with the more common yellow colouration.
The second photo of the fish from behind clearly shows the triangular shape mentioned on 30 April.
Long Beach is without any doubt the Cape Town dive site with the most unusual sightings. False Bay has a slow counter-clockwise current. Long Beach and Simon's Town harbour are calm and protected from most weather, so probably form a trap for these fishes. As most seen are not strong swimmers, once they reach this calm area they are likely to stay.
See "Coastal Fishes of the Cape Peninsula and False Bay", now available from SURG and better dive shops in Cape Town, for more details.
Coastal fishes of the Cape Peninsula and False Bay, a divers' identification guide, G Zsilavecz, 2005.
Coastal Fishes of Southern Africa. PC Heemstra & E Heemstra, 2004
Smiths' Sea Fishes, MM Smith and PC Heemstra, 1986.
More reef fishes and nudibranchs, D King & V Fraser, 2001.