Southern Pygmy Pipehorse, Idiotropiscis australis (Waite & Hale 1921)

Other Names: Little Pipehorse, Southern Little Pipehorse

A Southern Pygmy Pipehorse, Idiotropiscis australis, at Edithburg Jetty, Wool Bay, Gulf St Vincent, South Australia. Source: Simon Cribbes / Atlas of Living Australia. License: CC By Attribution

A small rare well camouflaged amongst red algae.

Cite this page as:
Bray, D.J. & Thompson, V.J. 2018, Idiotropiscis australis in Fishes of Australia, accessed 15 Jul 2020,

Southern Pygmy Pipehorse, Idiotropiscis australis (Waite & Hale 1921)

More Info


Endemic to temperate waters of southern and southwestern Australia, from Cape Jarvis and the Gulf St Vincent, South Australia, and Carnac Island, Western Australia

Inhabits shallow algal-covered reefs where it is well-camouflaged amongst algae and seagrasses. Individuals appear to be site attached, remaining in the same area for several years.


Dorsal fin 15–16; Anal fin 3–4; Pectoral fin 14–15; Trunk rings 12; Tail rings 37-39.

Body moderately elongate, head directed at slight angle to line of body; head and body sometimes head with fleshy flaps and filaments; superior trunk and tail ridges discontinuous; lateral trunk ridge not confluent with lateral tail ridge; tail prehensile. 

Dorsal fin short-based, on middle of back; anal fin tiny, below rear end of dorsal fin; caudal fin absent; pectoral fin very small.


This very small species only reaches a length of 55 mm.


Colour variable, usually plain, sometimes with dark bars on body sides; dorsal fin often with a brown anterior blotch. Females dark tan, green or yellow to whitish. Males are usually whitish to bright blue with dark bars on side and a bright scarlet red opercle.


Unknown, but likely to feed on small crustaceans.


Males brood the developing embryos in a sac-like brood pouch beneath their tail before the larvae are born alive. The brood pouch does not have separate bilateral membranous folds.

Two males collected near Carnac Island, Western Australia were brooding 10 and 80 eggs.


Although this rare pipehorse has been taken in dredges, it is of no interest to fisheries or aquaculture.


IUCN Red List of Threatened Species: Data Deficient

Australian Commonwealth legislation: Marine listed under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

State Legislation: Listed as protected under the South Australian Fisheries Management Acts.

CITES: Not listed.


Similar Species

Differs from Sydney’s Pygmy Pipehorse, Idiotropiscis lumnitzeri, in having 12, versus 11 trunk rings, and in having a much longer trunk than is almost twice the head length. I. australe differs from Helen's Pygmy Pipehorse, Idiotropiscis larsonaein having a less elevated and anteriorly protruding frontal ridge, more trunk rings (12 versus 11), more pectoral-fin rays (14–15 versus 12–13), and a longer snout.


Idiotropiscis is from the Greek idio- (individual, personal) and tropikos (of turning, figurative). The specific name australe is from the Latin australis (southern) in reference to the type locality in southern Australia.

Species Citation

Acentronura australe Waite & Hale 1921, Rec. S. Aust. Mus. 1(4): 317, fig. 53. Type locality: St Vincent Gulf, South Australia.


Bray, D.J. & Thompson, V.J. 2018


Australian Faunal Directory

Southern Pygmy Pipehorse, Idiotropiscis australis (Waite & Hale 1921)


Dawson, C.E. 1984. A new pipehorse (Syngnathidae) from Western Australia, with remarks on the subgenera of Acentronura. Japan. J. Ichthyol. 31(2): 156–160.

Dawson, C.E. 1985. Indo-Pacific Pipefishes (Red Sea to the Americas). Gulf Coast Research Laboratory, Ocean Springs, Mississippi. 230 pp. [as Acentronura (Idiotropiscis) australe]

Foster, S.J. & A.C.J. Vincent. 2004. Life history and ecology of seahorses: implications for conservation and management. J. Fish Biol. 65: 1–61.

Hutchins, J.B. 2001. Checklist of the fishes of Western Australia. Rec. West. Aust.  Mus. Suppl. 63: 9–50.

Kendrick, A.J. & Morgan, S. 2006. Idiotropiscis australe. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.1. . Downloaded on 08 April 2010. 

Kuiter, R.H. 2004. A new pygmy pipehorse (Pisces: Syngnathidae: Idiotropiscis) from eastern Australia. Rec. Aust. Mus. 56(2): 163–165.

Kuiter, R.H. 2008. Family Syngnathidae (pp. 448–479). In Gomon, M.F., D.J. Bray & R.H. Kuiter (eds) Fishes of Australia's Southern Coast. New Holland Press & Museum Victoria, Melbourne, Australia, 928 pp.

Kuiter, R.H. 2009. Seahorses and their relatives. Aquatic Photographics, Seaford, Australia. Pp. 1–333.

Kendrick, A.J. & G.A. Hyndes. 2003. Patterns in the abundance and size distribution of syngnathid fishes among habitats in a seagrass-dominated marine environment. Estuar. Coast. Shelf Sci. 57: 631–640.

Paxton, J.R., J.E. Gates, D.F. Hoese & D.J. Bray. 2006. Syngnathidae (Pp. 810–846). In  Beesley, P.L. & Wells, A. (Eds) Zoological Catalogue of Australia. Volume 35. Fishes. ABRS & CSIRO Publishing, Australia., 3 vols.

Pogonoski, J.J., D.A. Pollard & J.R. Paxton. 2002. Conservation Overview and Action Plan for Australian Threatened and Potentially Threatened Marine and Estuarine Fishes, Environment Australia, Canberra. 375 pp.

Waite, E.R. & H.M. Hale. 1921. Review of the lophobranchiate fishes (pipe-fishes and seahorses) of South Australia. Rec. S. Aust. Mus. 1(4): 293–324.

Quick Facts

CAAB Code:37282034

Conservation:IUCN Data Deficient; EPBC Marine Listed

Depth:0-30 m

Habitat:Reef associated

Max Size:5.5 cm TL


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CAAB distribution map