Fish
Koester Rockcod
Acanthistius sebastoides
A small, heavy-headed reef rockcod of the South African coast, pale grey-brown with scattered orange spots and a blue-tipped tail, reaching about 40 cm.
Also known as common koester, koester, koester rock cod
- Typical size
- Attains about 40 cm
- Habitat
- Rocky reef, gullies and rock pools
- Depth
- to ~30 m
The koester is a stocky, large-mouthed rockcod that grows to around 40 cm, though most fish are smaller. It is pale grey-brown, peppered with small orange spots and a few darker blotches, with dark grey caudal and anal fins, dusky yellow pelvic fins and a distinctive blue tip to the tail. Colour varies a good deal from fish to fish. It is an ambush predator, lying motionless among the rocks and taking crabs, small fish and other invertebrates.
It ranges along the South African coast, broadly from Namibia to East London, and is one of the more common rockcods on the Eastern Cape shore. The koester keeps to broken ground - rock pools, deeper gullies and reef - from the shallows down to about 30 m, and is strongly territorial, holding the same patch for life. Anglers know it as a bait-robber that bolts straight into a hole when hooked, which makes it hard to land despite its size, and it is regarded as good eating.