Knifesnout Pipefish, Hypselognathus rostratus (Waite & Hale 1921)

Other Names: Knife-snout Pipefish, Knife-snouted Pipefish

Head of a Knifesnout Pipefish, Hypselognathus rostratus, amongst Posidonia seagrass in Tin Mine Cove, Wilsons Promontory, Victoria, 15 March 2015. Source: Robert Gardiner via Redmap Australia. License: All rights reserved


A large mottled brown pipefish sometimes with indistinct pale bars across the back, and pale spots along the underside. Knifesnout Pipefish have a low ridge along the top of the snout. 

Adults are very well-camouflaged amongst the seagrass Posidonia. In Port Phillip, Victoria, juveniles often shelter amongst floating weeds and jellyfish when oceanic waters run into the bay.

Cite this page as:
Bray, D.J. & Thompson, V.J. 2018, Hypselognathus rostratus in Fishes of Australia, accessed 23 Jul 2024,

Knifesnout Pipefish, Hypselognathus rostratus (Waite & Hale 1921)

More Info


Endemic to southern Australia from the Gippsland Lakes, Victoria, to Venus Bay, South Australia, and northern Tasmania. Inhabits seagrass beds and adjacent sand flats in coastal bays and estuaries to depths of about 15 m. Large adults often occur amongst Posidonia, whereas juveniles are often shelter in Zostera beds. Juveniles may also be found amongst floating algae and seagrass leaves. 


Dorsal fin 30–35; Anal fin 3–4; Pectoral fin 12–14; Caudal fin 10; Trunk rings 24–25; Tail rings 41–44; Subdorsal rings 2.50–0.75 + 6.25–8.25 = 8.00–9.50.

Body slender and elongate; trunk shallow; head aligned with body; body posterior to dorsal fin slightly longer than that before dorsal fin; body and head surfaces, excluding ridge margins, essentially smooth; small rounded wart-like scutella on body rings; snout very long, length 62–77% HL; snout relatively shallow, depth 7–16% snout length; opercles with poorly defined longitudinal ridge in adults, crossing one third or more of opercles in juveniles; tail not prehensile.

Single dorsal fin centrally on back with base of moderate length; anal fin tiny, below front half of dorsal fin; caudal fin small, rounded; pectoral fins small; ventral fins absent.


Maximum length more than 40 cm TL.


Mainly brownish, plain or with pale mottling and blotches, sometimes with diffuse pale bars dorsally.


Unknown, but likely to feed on tiny crustaceans.


Males incubate the developing young in a pouch on the underside of the trunk. Juveniles have a long pelagic stage and may periodically drift into large estuaries amongst floating weeds.


Infrequently taken as bycatch in dredges and trawls.


EPBC Act: Marine listed

State Government Legislation: Listed as protected under Victorian, Tasmanian and South Australian Fisheries Management Acts.


Knifesnout pipefish are taken infrequently in seine nets, dredges and trawls in shallow coastal seagrass beds. Juveniles are often collected in plankton nets near the surface in Port Phillip. Brooding males are very rare.

Similar Species

Differs from Hypselognathus horridus in having a rounded, wart-like scutella on each body ring, in lacking spines on head and body surfaces, and in having fewer trunk and tail rings (25 and 41–44 versus 27 and 42–45), more pectoral fin rays (12–14 versus 10–12), and a longer, shallower snout.

Although Knifesnout Pipefish may be confused with the Crested Pipefish, Histiogamphelus briggsii, the upper and lower margins of the snout of Hypselognathus rostratus are more or less parallel, whereas the Crested Pipefish has a rounded crest on its snout.


Hypselognathus is from the Greek hypselos meaning high and gnathos for jaw. The specific name, rostratus, is from the Latin, rostrum, meaning a beak or snout.

Species Citation

Histiogamphelus rostratus Waite & Hale 1921, Rec. S. Aust. Mus. 1(4): 303, fig. 44, Spencer Gulf, South Australia.


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


Australian Faunal Directory

Knifesnout Pipefish, Hypselognathus rostratus (Waite & Hale 1921)


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.

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

Kuiter, R.H. 1993. Coastal Fishes of South-eastern Australia. Crawford House Press, Bathurst. 437 pp.

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

Kuiter, R.H. 2008. Family Syngnathidae (pp. 448-479). In Gomon M.F., D.J. Bray & R.H. Kuiter (eds.) The fishes of Australia’s southern coast. New Holland Publishers, Chatswood, AustraliaState Print, Adelaide. 928 pp. 

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

Last, P.R., Scott, E.O.G. & Talbot, F.H. 1983. Fishes of Tasmania. Hobart : Tasmanian Fisheries Development Authority 563 pp. figs.

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. 

Scott, T.D., Glover, C.J.M. & Southcott, R.V. 1974. The Marine and Freshwater Fishes of South Australia. Adelaide : Government Printer 392 pp. figs.

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. 1948. Studies in Ichthyology No. 13. Records of the Australian Museum 22(1): 70-94 figs 1-11

Quick Facts

CAAB Code:37282012

Biology:Males brood the eggs

Conservation:EPBC Act Marine listed

Depth:0-15 m

Habitat:Seagrass beds, nearby sand flats

Max Size:40+ cm TL


Species Maps

CAAB distribution map