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 rare mottled or plain brownish to reddish-brown pipehorse or greyish pipehorse often covered in fleshy flaps and filaments, and sometimes a pale snout. The Southern Pygmy Pipehorse is extremely well-camouflaged amongst algae and seagrasses.

Cite this page as:
Bray, D.J. & Thompson, V.J. 2020, Idiotropiscis australis in Fishes of Australia, accessed 29 May 2024,

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

More Info


Endemic to southern Australia, from Cape Jarvis and the SA Gulfs, and the Perth area, Western Australia.

Inhabits shallow algal-covered reefs, sheltering among algae and seagrasses. Individuals may 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.


A small pipehorse, reaching a length of 55 mm.


Colour variable, usually plain, sometimes mottled or with darker 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.


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.


The specific name australe is presumably derived 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. 2020


Atlas of Living Australia

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. Japanese Journal of Ichthyology 31(2): 156-160 figs 1-3 (as Acentronura australe)  

Dawson, C.E. 1985. Indo-Pacific Pipefishes (Red Sea to the Americas). Ocean Springs (Mississippi) : Gulf Coast Research Laboratory 230 pp. 293 figs pl. 1. [as Acentronura (Idiotropiscis) australe]  

Dawson, C.E. 1994. Family Syngnathidae. pp. 440-475 figs 391-426 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. (as Acentronura australe

Foster, S.J. & Vincent, A.J.C. 2004. Life history and ecology of seahorses: implications for conservation and management. Journal of Fish Biology 65: 1–61. (as Acentronura australe

Hamilton, H., Saarman, N., Short, G., Sellas, A.B., Moore, B., Hoang, T., Grace, C.L., Gomon, M., Crow, K. & Simison, W.B. 2016. Molecular phylogeny and patterns of diversification in syngnathid fishes. Molecular Phylogenetics and Evolution 107: 388-403 + supplement 1-4 + 5.

Kendrick, A.J. & Hyndes, G.A. 2003. Patterns in the abundance and size distribution of syngnathid fishes among habitats in a seagrass-dominated marine environment. Estuarine and Coastal Shelf Science 57: 631–640. (as Acentronura australe

Kuiter, R.H. 2000. Seahorses, Pipefishes and Their Relatives. Chorleywood, UK : TMC Publishing 240 pp. 

Kuiter, R.H. 2004. A New Pygmy Pipehorse (Pisces: Syngnathidae: Idiotropiscis) from Eastern Australia. Records of the Australian Museum 56: 163-165 

Kuiter, R.H. 2008. Syngnathidae. pp. 448-479 in Gomon, M.F., Bray, D.J. & Kuiter, R.H. (eds). Fishes of Australia's Southern Coast. Sydney : Reed New Holland 928 pp. 

Kuiter, R.H. 2009. Seahorses and their relatives. Seaford, Australia : Aquatic Photographics pp. 331.

Kuiter, R. & Kuiter, S. 2018. Coastal sea-fishes of south-eastern Australia. Seaford, Victoria : Aquatic Photographics, 371 pp.

Pollom, R. 2016. Acentronura australe (errata version published in 2017). The IUCN Red List of Threatened Species 2016: e.T61314A115204241. Downloaded on 23 September 2020.

Waite, E.R. & Hale, H.M. 1921. Review of the lophobranchiate fishes (pipe-fishes and sea-horses) of South Australia. Records of the South Australian Museum (Adelaide) 1(4): 293-324 figs 39-56

Whitley, G.P. 1947. New sharks and fishes from Western Australia. Part 3. The Australian Zoologist 11(2): 129-150 figs 1-3 pl. 11 (as Idiotropiscis australe)

Quick Facts

CAAB Code:37282034

Conservation:IUCN Data Deficient

Depth:0-30 m

Habitat:Reef associated

Max Size:5.5 cm TL


Species Maps

CAAB distribution map