Abudefduf septemfasciatus
A grey-and-cream reef damsel banded like a barcode, logged from the Society Islands to Okinawa in water around 26-29C year-round.
Grows to about 16 cm, with a deep, oval, disc-shaped body typical of damselfish. Base colour runs pale grey to whitish, overlaid with seven dark vertical bands running from back to belly, the trait that gives it its name. The bands are broad and even-spaced, without the sharp yellow-and-black contrast of some relatives, giving it a more washed-out, barcode look underwater.
Usually seen hovering singly or in loose small groups over reef flats and coral heads, picking at plankton and small invertebrates in the water column rather than grazing algae mats. It holds station over a patch of reef and will drift off a short distance as divers approach rather than bolting, then settle back once you move on. Most sightings come from shallow water down to about 20 metres, close to structure it can dart back into.
Like other Abudefduf damselfish, it lays flat sheets of eggs on cleared rock or dead coral, and the guarding parent will chase off far larger fish and even divers that linger too close to the nest.
No clear seasonal pattern shows up in the sightings, and it sits comfortably in 25.6 to 29.3C year-round, so any month works on the reefs where it is found.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
Most consistently logged in the Society Islands of French Polynesia, which accounts for the largest share of sightings, followed by the Inner Islands of Seychelles and Phuket in Thailand. Also a reliable find around Okinawa and the Ryukyu Islands in Japan, Java in Indonesia, Orchid Island in Taiwan, the Central Atolls of the Maldives, and Saint-Leu in Reunion.
Mapping where Seven-banded Sergeant-major is logged…
Best chances are in the Society Islands of French Polynesia and the Inner Islands of Seychelles, with further solid populations around Phuket in Thailand, Okinawa in Japan, and Java in Indonesia.
There is no strong seasonal pattern in the sightings, and it lives in warm water between roughly 25.6 and 29.3C, so it is present on tropical reefs throughout the year.
Look for a deep, oval damselfish around 16 cm with a pale grey to whitish body crossed by seven even dark vertical bands, hovering over reef structure rather than hugging the bottom.
They reach around 16 cm in length, putting them among the larger damselfish you will see on a reef, though still small compared to most other reef fish families.
No, they pose no danger to divers. They may approach or hold their ground when guarding an egg patch, but there is no sting or bite risk involved.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
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