Pycnochromis fieldi
Small reef damselfish split blue-and-white, most reliably logged in the Central Atolls of the Maldives at 26-29C, year-round.
A tiny damselfish, barely 4 cm, split cleanly down the middle: the front half of the body is pale grey to white, the back half a deeper blue-grey to almost black, with the divide often falling right around the dorsal fin. It has the classic chromis shape, slim and slightly deep-bodied with a forked tail, and swims in loose groups just off the reef structure. The sharp two-colour split is the single feature to look for; nothing else in its size class shows that clean a break.
Divers usually spot it hovering in small, loose groups a short distance above the reef, picking plankton out of the water column rather than grazing the substrate. It keeps a comfortable distance from divers but does not bolt for cover the way some damselfish do, making it an easy, unhurried subject once you slow down and let it settle back into its spot. Look for it over coral rubble and reef slopes rather than deep in crevices.
Like other chromis, it feeds mainly by picking zooplankton straight out of the current rather than nibbling algae off the reef, so you'll usually find it stationed in open water just above cover rather than tucked against it.
No clear seasonal pattern shows up in the sightings, and its comfort range of roughly 25.6 to 28.7C matches warm tropical reef water year-round, so there is no specific month to target. Plan around the destination's general dive season rather than the fish itself.
Reef neighbours a diver could mistake it for. Use the identification notes above to tell them apart.
This one is most reliably found in the Maldives, especially the Central Atolls and Southern Atolls, where it turns up on far more sites than anywhere else in its range. Outside the Maldives, look for it around Reunion's Saint-Paul region, Zanzibar in Tanzania, and Flic-en-Flac in Mauritius, with smaller but steady populations in KwaZulu-Natal (South Africa), Khao Lak (Thailand), Kenya, and Inhambane (Mozambique).
Mapping where Two-tone Chromis is logged…
The Maldives is by far the most reliable destination, particularly the Central and Southern Atolls. It's also a steady find around Reunion's Saint-Paul coast, Zanzibar in Tanzania, Flic-en-Flac in Mauritius, and reefs in Kenya, South Africa, Thailand, and Mozambique.
There's no strong seasonal pattern in the sightings, and it sits comfortably in water from about 25.6 to 28.7C, so it's present on tropical reefs throughout the year rather than tied to one season.
Look for a small damselfish, around 4 cm, cleanly split in colour: pale grey to white on the front half of the body and darker blue-grey to black on the rear half. It typically hovers in loose groups just above the reef rather than hiding in it.
They stay small, reaching only about 4 cm in length, which is typical for chromis in this family. That size, combined with the two-colour body, makes them easy to pick out even in a mixed school.
No, they pose no threat to divers. They're small plankton feeders that keep their distance and have no defensive behaviour worth noting around people.
Site and sighting data is aggregated from diver logs, iNaturalist and GBIF. For taxonomy and conservation status:
Yellowtail Clownfish
3,523 sites
