Endangered in its own range, and present in Lembeh because the aquarium trade put it there.
A cardinalfish to about 8 cm, silver-white with three black bars across the body, long trailing dorsal and anal fins, a deeply forked tail, and rows of fine white spots over the fins and rear body. It is unmistakable. The species is naturally restricted to a small area of the Banggai Islands off eastern Sulawesi, has a very small total range, and is listed as Endangered.
The population in Lembeh Strait is introduced, established from fish released or escaped in the course of the aquarium trade, and the same has happened at several other sites in Indonesia. That is worth stating plainly: seeing them here is not seeing them in their range. They shelter in small groups among the spines of Diadema urchins and in branching coral, and stay within a metre or two of that cover for life. There is no planktonic stage — males brood the eggs and then the young in the mouth, releasing fully formed juveniles — which is exactly why the natural range is so small and why introduced populations stay where they are put.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.