Dascyllus melanurus
Blacktail damselfish
The blacktail damselfish, known in Italian as damigella a quattro bande 6, is a small damselfish (Pomacentridae) 1 of about 8 cm, white with three black bars on the body and a mostly black tail. 2 3 It lives in groups above branching corals in sheltered lagoons and bays and takes refuge among the branches when someone approaches. 3 4
At a glance
Data from the scientific sources listed at the bottom.
Depth in the wild
1–10 m
Size
up to 8 cm
maximum total length
Temperature in the wild
24.6–31.7 °C
Where it lives
Western Pacific: from Sumatra to Vanuatu, north to the Ryukyu Islands and south to New Caledonia, with a more recent record from Tonga. 2 In Australia it lives on the offshore reefs of the north-west, at Ashmore Reef, on the northern Great Barrier Reef and at least as far as Moreton Bay. 3
Conservation
IUCN Red List: least concern (2021). Red List data taken from FishBase and GBIF. 2 5 It does not appear in the CITES lists checked on Species+. 7 It is among the marine fish most imported into the United States: between 1.6% and 2.0% of the specimens imported in 2008, 2009 and 2011. 11
How to recognise it
Tap a number on the photo: the key explains what to look for.
Life in the wild
Where it is found
Sheltered lagoons, harbours and coastal inlets, usually at 1-10 m, often in groups of 20-30 fish on isolated Acropora heads. 3 It is also found on more open bottoms with outcrops of Acropora. 2 FishBase and Reef Life Survey give an overall range of 1-68 m. 2 4 In Reef Life Survey counts it was observed in the sea between 24.6 and 31.7 °C. 4 In Kimbe Bay (Papua New Guinea) it was found only on the reefs around the islands. 9
Behaviour
Active by day. 2 It lives in small groups above the coral and retreats among the branches if disturbed. 4 The genus Dascyllus depends closely on the corals it lives in. 3 In choice tests, newly settled juveniles preferred the smell of others of the same species and avoided that of other species, except for a neutral response towards Dascyllus reticulatus. 8
Reproduction
Distinct pairs form when breeding. 2 The eggs stay on the bottom, stuck to the substrate, and the male guards and fans them. 2 For the genus Dascyllus, Fishes of Australia reports that some species can change sex from female to male and that one or two dominant males defend a coral head with a harem; this is not a figure specific to this species. 3
In the aquarium
From the experience of the BallingMania community.
It is a community fish, and it is extremely aggressive towards species of the same family; very territorial, it is not recommended for beginner aquarists as it readily attacks both large fish and the aquarist's hand. It adapts to any situation, and if introduced as the first fish it is hard to add others; to reduce its aggression it should never be kept with other identical specimens or ones with a similar livery. By day it lives on the reef front or above the reef, while at night it hides under the rocks; it is an omnivorous fish and gets used to dry food easily; once placed in the aquarium it needs a couple of days to settle; if you decide to add it to the tank, keep it as the last fish; once it has found its territory it will clear out all the fish that swim around it. It differs from its cousin Dascyllus quadrifasciatus in the number of black bands.
Photo by: Vancouver Aquarium
Did you know?
Sources
- Froese R., Pauly D. (eds.), via WoRMS (2026). Dascyllus melanurus Bleeker, 1854. World Register of Marine Species.
- Froese R., Pauly D. (eds.) (2026). Dascyllus melanurus, Blacktail humbug. FishBase.
- Bray D.J. (2025). Dascyllus melanurus in Fishes of Australia. Museums Victoria.
- Reef Life Survey (2026). Dascyllus melanurus. Reef Life Survey.
- GBIF Secretariat (2026). Dascyllus melanurus, IUCN Red List category. GBIF.
- GBIF Secretariat, da Catalogue of Life (2026). Dascyllus melanurus, nomi comuni. GBIF.
- UNEP-WCMC, Segretariato CITES (2026). Search for Dascyllus melanurus in the CITES lists. Species+.
- Coppock A.G., Gardiner N.M., Jones G.P. (2016). Sniffing out the competition? Juvenile coral reef damselfishes use chemical cues to distinguish the presence of conspecific and heterospecific aggregations. Behavioural Processes.
- Dixson D.L., Jones G.P., Munday P.L., Pratchett M.S., Srinivasan M., Planes S., Thorrold S.R. (2011). Terrestrial chemical cues help coral reef fish larvae locate settlement habitat surrounding islands. Ecology and Evolution.
- Lawler A.R., Ogle J.T., Donnes C. (1977). Dascyllus spp.: new hosts for lymphocystis, and a list of recent hosts. Journal of Wildlife Diseases.
- Rhyne A.L., Tlusty M.F., Szczebak J.T., Holmberg R.J. (2017). Expanding our understanding of the trade in marine aquarium animals. PeerJ.
Sources checked on 5 November 2026. Community texts and ratings are kept separate from the scientific data.