Hardwicke’s pipefish (Solegnathus hardwickii)

Also known as: pallid seahorse, pipehorse
Synonyms: Hippocampus hardwickii, Syngnathus hardwickii
GenusSolegnathus (1)
SizeTotal length: 23.5 - 51 cm (1)
Top facts

Hardwicke’s pipefish is classified as Data Deficient (DD) on the IUCN Red List (1).

Hardwicke’s pipefish (Solegnathus hardwickii) belongs to the Syngnathidae family, which is named after the Greek wordsyngnathus meaning ‘fused jaw’ (2). The longest and thickest member of its family, Hardwicke’s pipehorse also has the highest number of body rings (3). Its body is almost entirely covered with rounded projections, or tubercles, and its back is flat or slightly curved. This species also has a short spine on the back of the snout (4).

The body of Hardwicke’s pipefish is yellowish-brown, with blackish edges on the ridges of its back and tail (3). It has dark but faint diagonal barring on the sides of its tube-like snout and across each eye, and dusky bars on the underside of the first half of the tail. Its fins are translucent (4), and its eyes are golden with black streaks (3).

Male Hardwicke’s pipefish have a ‘brood pouch’ situated on the tail which has five to eight brood compartments (4). The pear-shaped eggs laid by female Harwicke’s pipefish may be yellow, orange or amber in colour (1). 

Hardwicke’s pipefish is known from the South China Sea northwards to southern Japan, and from the western Indian Ocean in Mauritius. This species is also found in northern and Western Australia (1). 

Despite reliable indications that Hardwicke’s pipefish associates with certain habitat types such as deep water at the edge of coral reefs, these associations are unconfirmed at present. This species is mostly captured among trawled species which have been caught at depths of 12 to 100 metres, although it has also been collected in water as deep as 180 metres. In Australia, Hardwicke’s pipefish is reported as bycatch associated with sea fans, black corals, algae and sponges (1). 

There is currently very little information available on the life history of Harwicke’s pipefish. However, species within the Syngnathidae family are known to feed on crustaceans and it is therefore probable that this species has a similar diet (1). Members of this group feed using their tube-like snout to suck up prey through a small mouth (5).

Seahorses and pipefishes are unusual in that they both exhibit remarkable male parental care. In Harwicke’s pipefish the female lays pear-shaped eggs and transfers them to the male’s simple brood pouch using a specialised structure called an ovipositor (6). Within the brood pouch the eggs are surrounded by blood capillaries that give a ready supply of oxygen (1), and they are nourished and develop there until they are ready to hatch (6). 

The most severe threat to species such as Hardwicke’s pipefish is commercial trawling. This species is caught unintentionally as bycatch in fisheries intended for prawn and scallop, and is often sold for use in traditional medicine (1). Pipefish are intentionally collected for their reported pharmaceutical value (1) (4), and to be sold as curios and food in Asian markets (7).

Australian pipefishes are protected in Australian Commonwealth waters. As Hardwicke’s pipefish is found in Australian waters it is also protected under this law. Additionally, pipehorses in Australia’s Commonwealth waters are ‘listed marine species’ and are protected under the Environment Protection and Biodiversity Conservation Act 1999. To take, trade, injure or kill any of these listed marine species is illegal, unless a permit is issued by the Minister of the Environment (1).

Hardwicke’s pipefish receives no specific protection in Indonesia or the Philippines, but all pipehorses are subject to the requirements of fisheries legislation in these areas (1).

Find out more about Hardwicke’s pipefish:

More on pipefishes and seahorses:

Learn more about marine conservation in Australia:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (February, 2013)
  2. BBC Nature - Syngnathidae (February, 2013)
  3. Kaup, J. (1856) Catalogue of Lophobranchiate Fish in the Collection of the British Museum. The British Museum, London.
  4. Dawson, C. (1982) Synopsis of the Indo-Pacific Genus Solegnathus (Pisces: Syngnathidae). Japanese Journal of Ichthyology, 29(2): 139-161.
  5. Guest, A. and Craig, J. (2011) Editorial: The biology of Syngnathidae: pipefishes, seadragons and seahorses. Journal of Fish Biology, 78: 1597-1602.
  6. Wilson, A., Ahnesjo, I., Vincent, A. and Meyer, A. (2003) The dynamics of male brooding, mating patterns, and sex roles in pipefishes and seahorses (Family Syngnathidae). Evolution, 57(6): 1374-1386.
  7. Carpenter, K. (2002) Syngnathidae. In: The Living Marine Resourcesof the Western Central Pacific. Volume 4: Bony Fishes Part 2 (Mugilidae to Carangidae). Food and Agriculture Organization of the United Nations, Rome. Available at: