Plectroglyphidodon dickii
A small dark damselfish with a pale tail bar, most reliably logged on reefs around Okinawa, Queensland and Orchid Island year-round.
A small, deep-bodied damselfish that reads almost black to dark brown underwater, with a pale, sometimes whitish bar crossing the base of the tail that gives it its name. At 7 cm it sits low over the reef, holding a tight territory rather than swimming in open water. The blunt head and compact oval body are typical damselfish shape, and the tail bar is the single mark worth checking against similar dark damsels.
Expect to find it holding a small patch of reef, usually low down among coral rubble or dead coral heads, rather than out in the water column. It's territorial in a low-key way, darting out to chase off smaller intruders before ducking back to cover, and it tends to ignore divers that keep a respectful distance rather than hovering directly over its patch.
Like most damselfish, it likely guards a patch of algae or invertebrate turf on the reef floor and will defend that patch against other fish, which is why you'll often see the same individual in the same spot on repeat dives.
No clear seasonal pattern shows in the sightings, and its comfort range of roughly 25 to 29.3 C covers most of the year on the reefs where it's found, so it's a fair year-round target rather than a seasonal one.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most consistently logged in Queensland, Australia and the Okinawa & Ryukyu Islands of Japan, with strong showing on Taiwan's Orchid Island and Green Island. It also turns up reliably at Saint-Leu in Reunion and in South Africa's KwaZulu-Natal, with smaller but steady numbers in Nosy Be, Madagascar and the Inner Islands of Seychelles.
Mapping where Blackbar Devil is logged…
Best bets are Queensland in Australia and Okinawa in Japan, both strong for sightings, followed by Orchid Island and Green Island in Taiwan. Saint-Leu in Reunion and KwaZulu-Natal in South Africa are also reliable spots.
There's no strong season in the data, and its warm-water niche of about 25 to 29 C holds year-round on the reefs it favours, so any time you're diving those regions is a reasonable time to look.
Look for a small, dark brown to blackish damselfish around 7 cm long, sitting close to the reef with a pale bar crossing the base of its tail. It behaves like a typical territorial damsel, staying near one patch rather than roaming.
They're small, topping out around 7 cm, and stay close to the reef structure rather than growing into anything you'd spot from a distance.
No. They're a small, non-aggressive reef damselfish that poses no threat to divers beyond the odd territorial dart if you get too close to their patch.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
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