Threefin Velvetfish, Neoaploactis tridorsalis Eschmeyer & Allen 1978

A Threefin Velvetfish, Neoaploactis tridorsalis, at Point Murat, Exmouth Gulf, Western Australia, June 2020. Source: Glen Whisson / License: CC By Attribution-NonCommercial

A small mottled dark to pale grey or pale brown velvetfish, with irregular white spots and blotches especially on the fins, a pale band behind the eye, and sometimes an orange head.
The Threefin Velvetfish has a deep notch between the 7th and 8th spines of the second dorsal fin, giving the appearance of three separate dorsal fins.

Cite this page as:
Bray, D.J. 2020, Neoaploactis tridorsalis in Fishes of Australia, accessed 21 Apr 2024,

Threefin Velvetfish, Neoaploactis tridorsalis Eschmeyer & Allen 1978

More Info


Patchy distribution from Rottnest Island to Exmouth Gulf, Western Australia, and off Townsville to One Tree Island, Queensland, and Victor Harbor to Spencer Gulf, South Australia, and off Point Dover, Western Australia in the Great Australian Bight. Elsewhere the species occurs in the west Pacific: New Guinea, Solomon Islands and New Caledonia.
Inhabits shallow sand and rubble areas near reefs, usually at depths above 5 m.


Dorsal fin IV + VIII, 9; Anal fin II, 8; Pectoral fin 12; Pelvic fin I, 3; Caudal fin 16; Lateral-line scales 11.
Body depth ~2.7-3.0 in SL; lachrimal bone with two diverging spines; rear margin of preopercle with five blunt spines, decreasing in size ventrally. Dorsal-fin origin above middle of eye; first dorsal fin with four spines separate by scales from the second fin; second dorsal fin with a deep notch between spines 7-8, giving the appearance of three separate dorsal fins. Scales highly modified, with a strong spinous flange or median shelf-like projection at right angles to the body, supported by an elongate diamond-shaped base embedded in the skin.


The specific name tridorsalis is from the Latin tri- (= three) and dorsalis (= dorsal, of the back) in reference to the appearance of three dorsal fins in this species.

Species Citation

Neoaploactis tridorsalis Eschmeyer & Allen 1978, Records of the Western Australian Museum 6(4): 444, figs 1-2. Type locality: One Tree Island, Capricorn Group, Queensland, 3-4 m.


Bray, D.J. 2020


Atlas of Living Australia

Threefin Velvetfish, Neoaploactis tridorsalis Eschmeyer & Allen 1978


Allen, G.R. 1997. Marine Fishes of Tropical Australia and South-east Asia. Perth : Western Australian Museum 292 pp. 106 pls.

Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research 3 vols, 1260 pp.

Allen, G.R. & Swainston, R. 1988. The Marine Fishes of North-Western Australia. A field guide for anglers and divers. Perth, WA : Western Australian Museum vi 201 pp., 70 pls.

Baker, J., Shepherd, S., Brown, A., Crawford, H. & Muirhead, D. 2020. Uncommon and cryptic reef fishes along Fleurieu Peninsula. Report for Adelaide and Mt Lofty Ranges Natural Resources Management Board June 2008, 25 pp.

Eschmeyer, W.N. & Allen, G.R. 1978. Neoaploactis tridorsalis, a new genus and species of fish from the Great Barrier Reef, Australia (Scorpaeniformes: Aploactinidae). Records of the Western Australian Museum 6(4) : 443-448. See ref online

Fricke, R., Kulbicki, M. & Wantiez, L. 2011. Checklist of the fishes of New Caledonia, and their distribution in the Southwest Pacific Ocean (Pisces). Stuttgarter Beitr├Ąge zur Naturkunde. Serie A (Biologie) Neue Serie 4: 341-463

Johnson, J.W. 2004. Two new species and two new records of aploactinid fishes (Pisces: Scorpaeniformes) from Australia. Records of the Australian Museum 56(2): 179-188 DOI: 10.3853/j.0067-1975.56.2004.1421

Johnson, J.W. 2008. Family Aploactinidae. pp. 501-503 in Gomon, M.F., Bray, D.J. & Kuiter, R.H. (eds). Fishes of Australia's Southern Coast. Sydney : Reed New Holland 928 pp. 

Poss, S.G. 1994. Family Aploactinidae. pp. 506-509 figs 451-453 in Gomon, M.F., Glover, C.J.M. & Kuiter, R.H. (eds). The Fishes of Australia's South Coast. Adelaide : State Printer 992 pp. 810 figs.

Poss, S.G. 1999. Families Scorpaenidae, Caracanthidae, Aploactinidae. pp. 2291-2358 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 4 pp. 2069-2790. 

Poss, S.G. & Eschmeyer, W.N. 1978. Two new Australian velvetfishes, genus Paraploactis (Scorpaeniformes : Aploactinidae) with a revision of the genus and comments on the genera and species of the Aploactinidae. Proceedings of the California Academy of Sciences 41(18): 401-426 figs 1-14 See ref at BHL

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

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

Quick Facts

CAAB Code:37290009

Depth:3-30 m

Habitat:Reef associated, sand/rubble areas

Max Size:4.5 cm TL

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Species Maps

CAAB distribution map