Blackfin Damselfish, Pomacentrus magniseptus Allen, Erdmann & Pertiwi 2017

A Blackfin Damselfish, Pomacentrus magniseptus, on Davies Reef, Great Barrier Reef, Queensland, November 2016. Source: Ian Shaw / License: CC by Attribution-NonCommercial

A charcoal-grey damselfish with a network pattern of broad dark scale margins, and a vertically oval pearly-white to pale-grey spot on each scale forming rows of pale spots along the side. The Blackfin Damselfish also has a large black spot covering pectoral-fin base, charcoal-grey dorsal, anal and caudal fins, blackish pelvic fins, and no scales on the preorbital bone and most of the suborbital bone.
This species has previously been confused with Pomacentrus philippinus which occurs off Western Australia.

Cite this page as:
Bray, D.J. 2017, Pomacentrus magniseptus in Fishes of Australia, accessed 24 Oct 2021,

Blackfin Damselfish, Pomacentrus magniseptus Allen, Erdmann & Pertiwi 2017

More Info


Great Barrier Reef, Queensland, from the northern part to the Capricorn Group in the south. The species is common and widespread on the Great Barrier Reef, typically inhabiting passages and outer reef slopes in depths of about 1.5–12 m, usually adjacent to vertical walls or in the shadows of overhanging cliffs and ledges.


Dorsal fin XIII,13–15 (usually 14); Anal fin II,13–15 (usually 14); Pectoral fin usually 17–19 (usually 18); Tubed lateral-line scales 16–19 (usually 18); Total gill rakers on first arch 21–24 (usually 23).

Body depth 1.9–2.1 in SL; scales usually absent on preorbital and suborbital, except occasional scales on posterior part of suborbital.


Generally charcoal grey with thick blackish scale margins producing a network pattern and a vertically ovate whitish spot centred on each scale, forming rows that correspond with horizontal scale rows; a large black spot on pectoral-fin base, invading outer part of axil; inner surface of pectoral-fin axil greyish; median fins charcoal grey to blackish; dorsal scleral surface of eye bright blue (Allen et al. 2017).

Similar Species

Pomacentrus magniseptus differs from other members of the P. philippinus species complex in having a distinctive color pattern of horizontal rows of whitish spots on the side of the body made up of the pale centres of the distinctly outlined scales. It further differs in always lacking scales on the preorbital and most of the suborbital; occasional specimens, however, possess 1–3 scales on the posteriormost section of the suborbital (Allen et al. 2017).


The specific name magniseptus is from Latin, meaning 'great-barrier', in reference to its Great Barrier Reef geographic distribution.

Species Citation

Pomacentrus magniseptus Allen, Erdmann & Pertiwi 2017, J. Ocean Sci. Foundn 25: 64, Figs 6C, 12–13. Type locality: Australia, Queensland, Great Barrier Reef, northern corner of Escape Reef, approximately 15°50’ S, 145°50’ E, 3–6 m


Bray, D.J. 2017

Blackfin Damselfish, Pomacentrus magniseptus Allen, Erdmann & Pertiwi 2017


Allen, G.R., Erdmann, M.V. & Pertiwi, P.D. (2017) Descriptions of four new species of damselfishes (Pomacentridae) in the Pomacentrus philippinus complex from the tropical western Pacific Ocean. Journal of the Ocean Science Foundation 25: 47–76. doi: PDF available, open access

Allen, G.R., Erdmann, M.V. & Pertiwi, P.D. (2017) Pomacentrus flavioculus, a new species of damselfish from Fiji and Samoa (Teleostei: Pomacentridae). Journal of the Ocean Science Foundation 28: 22–33. Open access, doi:

Randall, J.E., Allen, G.R. & Steene, R. 1990. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 507 pp. (as Pomacentrus philippinus)

Randall, J.E., Allen, G.R. & Steene, R. 1997. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 557 pp. (as Pomacentrus philippinus)

Quick Facts

Depth:1-12 m

Habitat:Reef associated

Max Size:8+ cm SL


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