It lives inside a coral. Not near one: inside, among the branches of a Pocillopora head, in the gaps between the arms where nothing larger than a finger can follow.
A branching coral colony is one of the safest addresses on a reef. The branches are hard, sharp and closely spaced, the spaces between them are shaped like the fish that use them, and a predator that wants in has to be small enough to get in, which means it is small enough not to matter. Whole communities live in there: damselfish, gobies, crabs, shrimps, and this dottyback.
The rent is size. Everything that lives in a coral head is limited to what fits between the branches, permanently, and a fish that outgrows its colony has to cross open reef to find another one. That single crossing is where most of them are eaten, which is why so many coral dwellers stay under ten centimeters for good.
Color is dark olive along the back with yellow underneath, or simply drab brown, and it is shallow, seldom below twenty meters. Watch one head of Pocillopora for a minute and it will come out.
The genus. Pseudochromis Rüppell 1835 - pseudo- (false). ETYFish
The species. Pseudochromis olivaceus Rüppell 1835 - olive-colored. ETYFish
- dark olive along the back, yellow underneath, or plain drab brown
- almost always among the branches of a Pocillopora head
- shallow water, rarely below twenty meters
- up to 9 cm
Why it's threatened
There are no known major threats.
Threat classification from the IUCN Red List.
