Pycnochromis dimidiatus
A small dark damselfish with a white-dipped tail, most reliably found on Red Sea reefs off South Sinai and Marsa Alam year-round.
A small, deep-bodied damselfish about 6 cm long, split cleanly into two colours: the front half of the body is dark chocolate-brown to black, the rear half and tail turn crisp white as if dipped, giving a sharp two-tone line down the flank. The fins are rounded and the body oval and compact, typical of the damselfish shape. Look for that clean colour break rather than any spots or stripes, it is the single most useful field mark on this fish.
Expect to see it hovering just above coral heads or ducking into branching coral for cover, usually in small loose groups rather than alone. It is not a fish that reacts dramatically to divers, drifting back into its patch of reef rather than fleeing outright, and it is logged across a wide depth range from the shallows down to over 30 metres. Most sightings describe it as an uncommon but steady presence rather than something that swarms a site.
Like most damselfish, it likely feeds on a mix of algae and small planktonic prey picked from the water column just above the reef, helping keep its patch of coral grazed and defended from competitors.
There is no strong seasonal pattern in the data, and with a comfortable range of roughly 25 to 29 C, Red Sea reefs sit within its preferred temperature band for most of the year, so it can be dived year-round.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
This is very much a Red Sea fish: it is most commonly logged in Egypt, especially South Sinai and Marsa Alam & the Deep South, with the Red Sea Riviera also holding a strong population. Smaller but consistent numbers turn up further north and east in Jordan's Aqaba, Saudi Arabia's Red Sea coast, and Eilat in Israel, so any Red Sea liveaboard or shore-diving trip in the region has a fair chance of it.
Mapping where Chocolate Dip Damselfish is logged…
They are most reliably found in the Egyptian Red Sea, particularly South Sinai and Marsa Alam & the Deep South, with the Red Sea Riviera also a strong area. Smaller numbers are logged in Jordan's Aqaba, Saudi Arabia's Red Sea coast, and Eilat in Israel.
There is no clear seasonal pattern in sightings, and Red Sea water temperatures generally stay within its comfortable range through the year, so it can turn up on any dive trip regardless of season.
Look for a small, oval damselfish with a sharp two-tone split: dark brown to black on the front half of the body, white on the rear half and tail. At around 6 cm it is easy to overlook among coral branches, so the clean colour break is the giveaway.
They stay small, reaching around 6 cm in length, which is typical for reef damselfish.
No, they pose no danger to divers. Like other damselfish they may dart at intruders near their coral patch, but this is a territorial display, not a threat to people.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
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