Abudefduf vaigiensis
Spot the bold black-and-yellow stripes of the Indo-Pacific Sergeant Major on reefs from the Maldives to Hawaii, present year-round in warm tropical waters.
Five broad black vertical bars on a pale yellow body make this small damselfish one of the easier reef fish to nail on sight, about 14 cm long, oval-bodied, and rarely hiding. Look for it in the shallows, often just a metre or two below the surface. Breeding males are a useful exception: they shift to a dark blue-grey overall, almost unrecognisable until you clock the same barred pattern beneath the wash. Non-breeding fish and females keep the classic yellow-and-black look year-round.
Bold and inquisitive, sergeant majors rarely flee when a diver approaches, they are more likely to drift closer and eye you with interest, especially if there is any disturbance stirring up the water. They are active during daylight hours, so day dives and snorkel sessions are ideal for watching them pick at small invertebrates and algae along the upper reef and rubble zones. Get close to a nest during breeding season and the mood changes fast: males guarding a patch of purple eggs become surprisingly assertive, fanning the eggs and charging anything that ventures too near.
When a male claims a nest site, he changes colour dramatically, shifting from yellow-and-black to a deep blue-grey, and guards the egg mass with an aggression that seems far outsized for a 14 cm fish.
Present year-round in both the Northern and Southern hemispheres, with no concentrated season detected across either. Comfortable across a temperature range of roughly 22 to 29 °C, it is at home on tropical and subtropical reefs through every month.
Most commonly logged across the Maldives and Indonesia, with very strong records also in the Philippines, the Egyptian Red Sea around Sharm el Sheikh, Malaysia, and Thailand. Hawaii stands out as the top single region in the United States, while Queensland and Bali round out the hotspots, essentially anywhere a tropical Indo-Pacific reef sits within 15 metres of the surface.
Mapping where Indo-Pacific Sergeant Major is logged…
They are logged across a wide sweep of the Indo-Pacific and Red Sea. The Maldives, Indonesia, and the Philippines see the most records, followed closely by Egypt's Sharm el Sheikh, Malaysia, Thailand, and Hawaii. Queensland in Australia and Bali are also reliable spots.
Any time of year works, sightings show no concentrated season in either hemisphere. As long as water temperatures sit somewhere between 22 and 29 °C, which describes most tropical reef destinations year-round, you have a solid chance of an encounter.
Look for a small, oval damselfish about 14 cm long with a pale yellow body crossed by five bold black vertical bars. It sits in shallow water, usually above 15 m, and rarely hides. Breeding males go dark blue-grey but keep the faint bar pattern, worth knowing so you do not write them off as a different species.
Typical adults reach around 14 cm. They are small enough that the five black bars are the feature you key on rather than size alone.
Yes, and they do it with real commitment. Males clean a patch of rock, spawn a clutch of purple eggs, then defend the nest aggressively against anything that approaches, including curious divers. During this phase the male's body colour shifts from yellow-and-black to a striking dark blue-grey.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Scissortail Sergeant
3,464 sites
