Almost everything on this site lives in the top forty meters, because that is where people go. This one mostly does not.
Its range runs from about fourteen meters down past a hundred and fifty, which puts the bulk of the population in what is called the mesophotic zone: the dim band below recreational diving and above the deep sea, roughly thirty to a hundred and fifty meters, where there is still light but not much. It is the least explored habitat on any coral coast. Reaching it takes technical diving or a submersible, so most of what is known about it comes from a small number of expeditions, and the reliable result of those expeditions is that they keep finding species nobody had recorded.
The mesophotic reef also matters for the shallow one. It is cooler, it bleaches less, and there is an open argument about whether it can act as a refuge that reseeds the reefs above it after a bad summer.
The fish is a small pale cardinalfish with a large eye, which is the standard equipment for living where the light has mostly gone.
The genus. Ostorhinchus Lacepède 1802 - osteo- (bone) + rhynchus (snout). ETYFish
The species. Ostorhinchus bryx (Fraser 1998) - brýx (βρύξ). ETYFish
- small pale cardinalfish, translucent with a silvery belly
- large eye
- below about fifteen meters and mostly far deeper
- up to 5.2 cm
Why it's threatened
There are no known major threats.
Threat classification from the IUCN Red List.
