Western Spiny Seahorse, Hippocampus angustus Günther 1870

Other Names: Narrow-bellied Seahorse, Slender Seahorse, Western Australian Seahorse

A Western Spiny Seahorse, Hippocampus angustus, in Exmouth Gulf, Western Australia, January 2024. Source: Kristin Anderson / iNaturalist.org. License: CC by Attribution-NonCommercial


A relatively large slender whitish, yellow, orange or brownish to greyish seahorse with a tall spiky coronet, a pattern of fine white, yellow, orange or brown scribbly or net-like markings and 5-6 distinctive dark irregular stripes across the snout. The dorsal fin has a narrow dusky submarginal margin band.

Cite this page as:
Bray, D.J. & Thompson, V.J. 2024, Hippocampus angustus in Fishes of Australia, accessed 23 Jul 2024, https://fishesofaustralia.net.au/home/species/1534

Western Spiny Seahorse, Hippocampus angustus Günther 1870

More Info


Shark Bay, north to the Dampier Archipelago, Western Australia. Inhabits sheltered bays with soft corals and soft sediment substrates adjacent to coral reefs, including seagrass beds.


Dorsal fin 17-19 (usually 18); Pectoral fin 15-19 (usually 16-17); trunk rings 11; tail rings 32-35 (usually 33-34); subdorsal rings 2 + 1.

Body slender; head angled downward from longitudinal axis of trunk; snout long, length 2.2 (2.0-2.5) in head length.
Spines well-developed, tips blunt or sharp, usually low in neck region; cheek spines sharp, double; double spine below eye; eye spine sharp, prominent; subdorsal spines 3/0,1,0.
Coronet moderately high with 5 well-developed sharp divergent spines.
Dorsal fin short-based.
A series of small pores, more or less distinct, extending to 20th tail ring, pores difficult to detect posteriorly.


Height to 160 mm.


Overall grey to brownish, orange or reddish, often with a combination of white, yellow, orange or brown fine scribbly or net-like markings on the head and body; 5-6 distinctive dark irregular stripes across the snout; and a narrow dusky submarginal band on the dorsal fin. In preservative - pale brown with thin dusky bars on snout and scribble markings on head and body.


Like other seahorses, this species presumably feeds by sucking small crustaceans and other planktonic organisms into its mouth.


The sexes are separate and it is the male seahorse that broods the developing young. The female deposits her eggs into an elaborate enclosed pouch on the abdomen of the male. He fertilizes the eggs inside the pouch and provides physical protection for the developing embryos. He also osmoregulates and aerates the embryos and may even provide some nourishment until the tiny young are born. The larvae are miniature versions of the adults and are independent once they leave the pouch.


Although taken as bycatch in commercial trawls, this species is not traded commercially.


CITES Listed: Listed under Appendix II of the Convention on the International Trade in Endangered Species of Wild Flora and Fauna (CITES).
EPBC Act 1999: Marine Listed under the Federal Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act 1999)


Seahorses are very poor swimmers and rely on camouflage to blend in with their surroundings and avoid predators.

Similar Species

The Western Spiny Seahorse has been confused with Hippocampus histrix, H. spinosissimus and H. multispinus.


The specific name is from the Latin angustus (= narrow), in reference to the narrow body of this species - "but little dilated in males, … females still narrower”.

Species Citation

Hippocampus angustus Günther 1870, Cat. Fish. Brit. Mus. 8: 200, Freycinet's Harbour (Shark Bay, Western Australia).


Bray, D.J. & Thompson, V.J. 2024


Atlas of Living Australia

Western Spiny Seahorse, Hippocampus angustus Günther 1870


Allen G.R. & R. Swainston. 1995. The marine fishes of north-western Australia: a field guide for anglers and divers. Western Australian Museum, Perth, Western Australia, 201 pp.

Günther, A. 1870. Catalogue of the fishes in the British Museum. 8: 1-549. (described as Hipocampus angustus from Shark Bay, and H. erinaceus - no type locality) See ref at BHL

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

Kuiter, R.H. 2001. Revision of the Australian Seahorse of the genus Hippocampus (Syngnathiformes: Syngnathidae) with descriptions of nine new species. Records of the Australian Museum 53: 293-340. https://doi.org/10.3853/j.0067-1975.53.2001.1350

Kuiter, R.H. 2009. Seahorses and their Relatives. Aquatic Photographics, Seaford, Australia.

Jones, A.G., Kvarnemo, C., Moore, G.I., Simmons, L.W. & Avise, J.C. 1998. Microsatellite evidence for monogamy and sex-biased recombination in the Western Australian seahorse Hippocampus angustus. Molecular Ecology 7(11): 1497-1505. https://doi.org/10.1046/j.1365-294x.1998.00481.x

Neira F.J., A.G. Miskiewicz & T. Trnski. 1998. Larvae of temperate Australian fishes: laboratory guide for larval fish identification. University of Western Australia press, Nedlands, Western Australia.

Pollom, R. 2017. Hippocampus angustus. The IUCN Red List of Threatened Species 2017: e.T107261486A54907188. https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T107261486A54907188.en. Accessed on 24 June 2024.

Short, G., Harasti, D. & Hamilton, H. 2019. Hippocampus whitei Bleeker, 1855, a senior synonym of the southern Queensland seahorse H. procerus Kuiter, 2001: molecular and morphological evidence (Teleostei, Syngnathidae). ZooKeys No. 824: 109-133. https://doi.org/10.3897/zookeys.824.30921

Quick Facts

CAAB Code:37282005

Conservation:IUCN Least Concern

Depth:0-63 m

Habitat:Reefs, macroalgae, seagrass

Max Size:22 cm TL


Species Image Gallery

Species Maps

CAAB distribution map