seahorses and seadragons

Hippocampus reidi. Photo by Melissa Rushby/Guylian Seahorses of the World.

Hippocampus reidi. Photo by Melissa Rushby/Guylian Seahorses of the World.

Many people are unaware that seahorses and seadragons are in fact fish. They have evolved some interesting adaptations to life in the sea. The combination of a horse-like snout (for sneaking up on small crustaceans), bony plates (to protect them against predators), and in the case of seahorses, a prehensile tail that allows them to cling to seagrasses, corals, and other holdfasts in ocean currents, has enabled these slow-swimming animals to survive for millions of years.

There are 44 recognised species of seahorses. Given their superior camouflage and the subtle differences between some species, taxonomists have long struggled on delineating and identifying them based on appearance alone. The rise of genomics and other molecular techniques will hopefully shed light on this matter and eventually provide a much clearer picture.

The seadragons consist of only three recognized species, the weedy seadragon (Phyllopteryx taeniolatus), the leafy seadragon (Phycodurus eques) and the newly described ruby seadragon (Phyllopteryx dewysea). They are more mobile than seahorses and tend to orient at a more horizontal angle than their cousins.

Check out the profiles of the species we currently recognize below (Lourie et al, 2016).


Photo Scientific Name Common Name IUCN Red List Status Profile Range
 abdominalis_fuchberger_SOTW_sm Hippocampus abdominalis
Lesson, 1827
Bigbelly seahorse LC icon_iseahorselogo_wikilogo_eolGBIFurl Australia & New Zealand
h.algiricus_sm H. algiricus
Kaup, 1856
West African seahorse VU icon_iseahorselogo_wikilogo_eolGBIFurl W. Africa
h.angustus_sm H. angustus
Günther, 1870
Narrow-bellied seahorse LC icon_iseahorselogo_wikilogo_eolGBIFurl N. Australia
h.barbouri_sm H. barbouri
Jordan & Richardson, 1908
Barbour's seahorse VU icon_iseahorselogo_wikilogo_eolGBIFurl Indo-Pacific
h.bargibanti_sm H. bargibanti
Whitley, 1970
Bargibant's pygmy seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl Indo-Pacific
h.breviceps_sm H. breviceps
Peters, 1869
Short-head seahorse LC icon_iseahorselogo_wikilogo_eolGBIFurl S. Australia
h.camelopardalis_sm H. camelopardalis
Bianconi, 1854
Giraffe seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl W. Indian Ocean
capensis H. capensis
Boulenger, 1900
Cape seahorse EN icon_iseahorselogo_wikilogo_eolGBIFurl S. Africa
h.waleananus H. casscsio
Zhang, Qin, Whang & Lin, 2016
Beibu Bay seahorse DD logo_wikiGBIFurl China
h.waleananus H. colemani
Kuiter, 2003
Coleman's pygmy seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl Indo-Pacific
h.comes_sm H. comes
Cantor, 1849
Tiger-tail seahorse VU icon_iseahorselogo_wikilogo_eolGBIFurl SE Asia
h.coronatus_sm H. coronatus
Temminck & Schlegel, 1850
Crowned seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl Japan & South Korea
h.waleananus H. dahli
Ogilby, 1908
Lowcrown seahorse LC logo_wikilogo_eolGBIFurl Northern & Eastern Australia
h.waleananus H. debelius
Gomon & Kuiter, 2009
Softcoral seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl Red Sea
h.denise_sm H. denise
Lourie & Randall, 2003
Denise's pygmy seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl Indo-Pacific
h.erectus_sm H. erectus
Perry, 1810
Lined seahorse VU icon_iseahorselogo_wikilogo_eolGBIFurl W. Atlantic
h.waleananus H. fisheri
Jordan & Evermann, 1903
Fisher's seahorse  LC icon_iseahorselogo_wikilogo_eolGBIFurl  Pacific (Hawaii)
h.guttulatus_sm H. guttulatus
Cuvier, 1829
Long-snouted seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl Europe & Mediterranean
h.waleananus H. haema
Han, Kim, Kai & Senou, 2017
Korean seahorse NE logo_wikiGBIF Korea & Japan
h.hippocampus_sm H. hippocampus
(Linnaeus, 1758)
Short-snouted seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl Mediterranean,
W. Atlantic
h.histrix_sm H. histrix
Kaup, 1856
Thorny seahorse  VU  icon_iseahorselogo_wikilogo_eolGBIFurl W. Indian Ocean to Central Pacific
h.ingens_sm H. ingens
Girard, 1858
Pacific seahorse VU  icon_iseahorselogo_wikilogo_eolGBIFurl California to Peru
h.waleananus H. japapigu
Short, Smith, Motomura, Harasti & Hamilton, 2018
Japan pig pygmy seahorse NE Japan
h.waleananus H. jayakari
Boulenger, 1900
Jayakar's seahorse LC icon_iseahorselogo_wikilogo_eolGBIFurl Red Sea to Pakistan
h.waleananus H. jugumus
Kuiter, 2001
Collar seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl  Australia
h.kelloggi_sm H. kelloggi
Jordan & Snyder, 1901
Great seahorse  VU icon_iseahorselogo_wikilogo_eolGBIFurl Indo-Pacific to E. Africa to China & Australia
h.kuda_sm H. kuda
Bleeker, 1852
Spotted seahorse  VU icon_iseahorselogo_wikilogo_eolGBIFurl Indo-Pacific
h.minotaur_sm H. minotaur
Gomon, 1997
Bullneck seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl  S. Australia
 h.mohnikei_sm H. mohnikei
Bleeker, 1853
Japanese seahorse VU icon_iseahorselogo_wikilogo_eolGBIFurl Japan & Korea to Thailand
h.waleananus H. paradoxus
Foster & Gomon, 2010
Paradoxical seahorse DD logo_wikilogo_eolGBIFurl  SW Australia
h.waleananus H. patagonicus
Piacentino & Luzzatto, 2004
Patagonian seahorse VU icon_iseahorselogo_wikilogo_eolGBIFurl  Brazil to Argentina
h.waleananus H. planifrons
Peters, 1877
Flatface seahorse LC  logo_wikilogo_eolGBIF  Australia
h.pontohi_sm H. pontohi
Lourie & Kuiter, 2008
Pontoh's pygmy seahorse LC  icon_iseahorselogo_wikilogo_eolGBIFurl  Indo-Pacific
h.waleananus H. pusillus
Fricke, 2004
Pygmy thorny seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl New Caledonia
h.reidi H. reidi
Ginsburg, 1933
Slender seahorse NT  icon_iseahorselogo_wikilogo_eolGBIFurl  North Carolina to Brazil
h.waleananus  H. satomiae
Lourie & Kuiter, 2008
Satomi's seahorse DD icon_iseahorselogo_wikilogo_eolGBIFurl  Indo-Pacific
 h.sindonis_sm H. sindonis
Jordan & Snyder, 1901
Sindo's seahorse LC  icon_iseahorselogo_wikilogo_eolGBIFurl  Japan
h.spinosissimus_sm H. spinosissimus
Weber, 1913
Hedgehog seahorse VU  icon_iseahorselogo_wikilogo_eolGBIFurl  Indo-Pacific
h.subelongatus_sm H. subelongatus
Castelnau, 1873
West Australian seahorse DD  icon_iseahorselogo_wikilogo_eolGBIFurl  W. Australia
h.trimaculatus_sm H. trimaculatus
Leach, 1814
Three-spot seahorse VU  icon_iseahorselogo_wikilogo_eolGBIFurl  Indo-Pacific
h.waleananus H. tyro
Randall & Lourie, 2009
Tyro seahorse DD  icon_iseahorselogo_wikilogo_eolGBIFurl Seychelles
h.whitei_sm H. whitei
Bleeker, 1855
White's seahorse EN  icon_iseahorselogo_wikilogo_eolGBIFurl Solomon Islands, E. Australia
h.waleananus H. zebra
Whitley, 1964
 Zebra seahorse DD   icon_iseahorselogo_wikilogo_eolGBIFurl  Australia
h.waleananus H. zosterae
Jordan & Gilbert, 1882
 Dwarf seahorse LC   icon_iseahorselogo_wikilogo_eolGBIFurl  Gulf of Mexico


Photo Scientific Name Common Name Red List Status Profile Range
leaft-seadragon Phycodurus eques
Günther, 1856
Leafy seadragon LC logo_wikilogo_eolGBIFurl S. Australia
h.waleananus Phyllopteryx dewysea
Stiller, Wilson & Rouse, 2015
 Ruby seadragon DD logo_wikilogo_eolGBIFurl W. Australia
weedy-seadragon Phyllopteryx taeniolatus
Lacepède, 1804
Weedy seadragon, common seadragon LC icon_iseahorselogo_wiki logo_eolGBIFurl S. Australia

IUCN Red List key

EX = Extinct 
EW = Extinct in the Wild 
CR = Critically Endangered 
EN = Endangered 
VU = Vulnerable 
NT = Near Threatened 
LC = Least Concern 
DD = Data Deficient 
NE = Not Evaluated

(Click here for a full explanation of IUCN Red List categories.)

A note on ‘Data Deficient’ species: Species that are assessed as ‘Data Deficient’ are deemed to have insufficient information known about them to carry out a proper conservation assessment. Although such species are not assessed as threatened, we may find out that they in fact are, once enough data is obtained.

Banner image of leafy seadragon (Phycodurus eques) by Gaetano Gargiulo/Guylian Seahorses of the World