Manonichthys splendens
A small purple-and-yellow reef fish most reliably found tucked into crevices in Raja Ampat and Sulawesi, year-round in warm Coral Triangle water.
A slender, torpedo-shaped fish around 9 cm long, split cleanly into two colours: a rich purple-to-violet rear half and a yellow-to-orange front half and face. It swims with quick, darting bursts rather than gliding, often staying close to a hole or ledge it can dive into. The sharp two-tone split (not a gradient) is the main thing to key on underwater, since few small reef fish show that exact colour break.
Expect to find it hovering close to a coral head, rubble patch, or small cave mouth rather than out in open water, ready to dart inside the moment it feels crowded. It is logged as uncommon at most sites where divers see it at all, with a smaller number of sites where it shows up reliably, so patient, slow looking around structure pays off more than open-water scanning. Most sightings are on daytime dives at typical reef depths where these crevice-loving fish tend to concentrate.
Dottybacks in this family are known for aggressive, territorial behaviour disproportionate to their size, often chasing off fish far larger than themselves from a favoured crevice.
Sightings show no clear seasonal pattern, and the water it is found in sits in a narrow warm band of 27.6 to 29.0 C year-round across its Indonesian range, so there is no need to time a trip around a season. Any month works; go when you would go for the reef anyway.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
This one is very much a Coral Triangle fish: it turns up most often in Raja Ampat and across Sulawesi, Indonesia, with Raja Ampat producing the strongest run of sightings. A smaller but real presence has also been logged around Dili in Timor-Leste and in Nusa Tenggara, so it is not exclusively a Raja Ampat specialty even if that is where divers see it most.
Mapping where Splendid Dottyback is logged…
It is most reliably seen in Raja Ampat and around Sulawesi in Indonesia, with additional sightings logged near Dili in Timor-Leste and in Nusa Tenggara.
There is no strong season in the sighting data, and the water it favours stays in a warm 27.6 to 29.0 C range year-round, so it can be found on any month's dive trip to its Indonesian range.
Look for a small, slender fish around 9 cm with a sharp two-tone split: purple across the back half of the body and yellow to orange across the head and front. It tends to sit near holes and ledges rather than swim in open water.
They stay small, reaching roughly 9 cm in length, which keeps them tucked close to reef structure where they can duck for cover quickly.
No, it poses no danger to divers. It is a small, territorial reef fish that may dart at other fish near its patch but has no interest in and no capacity to threaten a diver.
Like other dottybacks, it can be surprisingly territorial for its size, defending a favourite crevice against fish considerably larger than itself.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Soldierfish
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