FishCommonVisible while snorkeling

Domino damselfish

Dascyllus trimaculatus

A velvet-black little fish with three snow-white dots – as if a domino tile had come to life among the corals.

Photo: iNaturalist – (c) Valued image, some rights reserved (CC BY-SA)

The domino damselfish (Dascyllus trimaculatus) is named after its simple yet elegant pattern: three white dots glow on its velvety black body – one on each flank and one on the forehead. The scientific name "trimaculatus" means exactly that: three-spotted. Curiously, adults gradually fade – the spots grow dim and may disappear entirely, so older fish look more greyish-black.

The most fascinating secret of this species is its childhood: tiny juveniles shelter among the tentacles of sea anemones just like clownfish, and sometimes even move in between the spines of long-spined sea urchins. As they grow, they outgrow the anemone and settle in loose groups around larger coral heads, darting between the branches at the first sign of danger. They feed on plankton and small bottom-dwelling invertebrates.

It is a very common species around Hurghada, and since it is at home in shallow lagoons and on reef tops, it is easy to watch while snorkeling too. Watching a large anemone where black domino juveniles bustle alongside the resident clownfish family is a special treat – two species sharing the same stinging bodyguard. Divers recognise them as the black clouds hovering around coral heads that vanish in unison at any threat.

Did you know?

Juvenile domino damselfish are immune to anemone stings just like clownfish – as youngsters they often share the very same anemone with a clownfish family, then simply "move out" of the parental home as they grow up.

Where can you meet it?

Look for it on shallow reefs rich in anemones and coral heads: on the El Fanadir plateau, at Gota Abu Ramada, around Abu Ramada and at the towers of El Aruk you are almost certain to meet it.

Frequently asked questions

Only as a juvenile: the few-centimetre youngsters hide among the anemone's tentacles, often together with clownfish. Adults live in groups around coral heads – for them the anemone is just a nursery.

Yes, very easily: it is a common resident of shallow reef tops and lagoons, and the black body stands out against pale corals from far away. In the shallows of Gota Abu Ramada an encounter is almost guaranteed.

It is a matter of age: the white spots are brightest on young fish, fade gradually with adulthood, and can vanish completely on old individuals. The "domino" pattern is mostly a youth outfit.