Denise' Pygmy Seahorse, Hippocampus denise Lourie & Randall 2003

Denise's Pygmy Seahorse, Hippocampus denise on an orange gorgonian coral

Denise's Pygmy Seahorse, Hippocampus denise. Source: Richard Smith © Richard Smith - License: All rights reserved


This tiny master of camouflage is less than 2 cm in length, and exactly matches the branches and polyps of its gorgonian sea fans hosts. Denise’s Pygmy Seahorse is orange with a relatively thin body covered in bumps, a long neck, a short snout and a long prehensile tail.

Denise’s Pygmy Seahorse lives primarily on gorgonian seafan colonies of the genus Annella, on which they are extremely well camouflaged. They have also been found on gorgonians of the genera Muricella and Echinogorgia.

Footage of Denise’s Pygmy Seahorse on the gorgonian Annella reticulata at a depth of 102 metres on Osprey Reef in the Coral Sea, May 2011, taken by the PICASSO-1 ROV from JAMSTEC. 

Fabulous footage of Denise' Pygmy Seahorse courtship, mating and birth of baby seahorses.

The ARKive project has fantastic images and video footage of Denise's Pygmy Seahorse camouflaged against gorgonian corals on which they live.

Cite this page as:
Dianne J. Bray, Hippocampus denise in Fishes of Australia, accessed 23 Sep 2020,

Denise' Pygmy Seahorse, Hippocampus denise Lourie & Randall 2003

More Info


In Australian waters, Hippocampus denise has only been found on Holmes Reef and Osprey Reef in the Coral Sea, ENE of Cairns. A specimen at Holmes Reef was collected from a species of the gorgonian octocoral, Villogorgia by an underwater remotely operated vehicle (ROV) at a depth of about 100 metres (elsewhere at depths of 13-90 metres).

Elsewhere, the species is widespread in the Western Pacific and has been recorded from Malaysia, Indonesia to Palau, Micronesia, Papua New Guinea, the Solomon Islands and Vanuatu.

Usually found in pairs on gorgonian octocorals Annella reticulata, Muricella, Echinogorgia and Villogorgia, at depths ranging from 13–102 m.


Dorsal fin 13-14; Pectoral fin 10-11; Anal fin; Trunk rings 12; Tail rings 27-31.


To 16.2 mm


Plain orange or orange with dark flecks, and slightly darker bands around the tail.


The sexes are separate, and males appear to brood the developing eggs entirely within the trunk region, with the entrance to the brooding cavity via a single post-anal slit.

Smith & Tibbetts (2008) observed a male giving birth at Wakatobi, Indonesia, after a gestation period of 11 days. "At dawn, the male (18.8 mm SL) emerged from a protected area of the gorgonian and turned outward from the seafan and forcefully expelled six to seven juveniles into the water column) ... The skin of the male was visibly wrinkled following parturition but soon after appeared to have been re-inflated, possibly with seawater. Thirty minutes after the male had given birth, the female transferred a new clutch of eggs. This involved the pair grasping tails, floating free from the gorgonian for several seconds and then the physical connection of the urino-genital openings. Four back-to-back pregnancies of this pair were observed; all births occurred  dawn fter a gestation period of 11 days."

Video footage shows one male giving birth to 13 darkly pigmented miniature seahorses which floated upwards in the water column. Males and females perform a courtship ritual before the female transfers her eggs to the male's brood pouch.


IUCN: Listed as DATA DEFICIENT on the IUCN Red List of Threatened Species.

Similar Species

Differs from the Pygmy Seahorse, Hippocampus bargibanti, in having a smoother body with fewer polyp-like tubercles; females are also more slender and elongate, whereas males are more rounded.


The species is named in honour of Denise Tackett, who first brought it to the notice of the authors, and has spent hundreds of hours underwater observing the behaviour of pygmy seahorses, especially Hippocampus bargibanti.

The name “Denise” also means “follower of Dionysus, the Greek god of wine; wild, frenzied”, and H. denise is more active than H. bargibanti (Lourie & Randall 2003).

Species Citation

Hippocampus denise Lourie & Randall 2003, Zool. Stud. 4(2): 286, Figs. 2, 4a, 4b, 5, 6-10. Type locality: Banta Island, Nusa Tenggara, Indonesia, 8°24'S, 119°17'E, depth 26 m. 


Dianne J. Bray


Australian Faunal Directory

Denise' Pygmy Seahorse, Hippocampus denise Lourie & Randall 2003


Brennan, E. May 2011. Pygmy seahorse and corals found at new depths. Australian Geographic Online.

Foster, R., T.C.L. Bridge & P. Bongaerts. 2012. The first record of Hippocampus denise (Syngnathidae) from Australia. aqua, International Journal of Ichthyology 18(1): 55 -57.

Gomon, M.F. & Kuiter, R.H. 2009. Two new pygmy seahorses (Teleostei: Syngnathidae: Hippocampus) from the Indo-West Pacific. Aqua, International Journal of Ichthyology 15(1): 37-44.

Lourie, S.A. & Kuiter, R.H. 2008. Three new pygmy seahorse species from Indonesia (Teleostei: Syngnathidae: Hippocampus). Zootaxa 1963: 54-68.

Lourie, S.A. & Randall, J.E. 2003. A new pygmy seahorse, Hippocampus denise (Teleostei: Syngnathidae) from the Indo-Pacific. Zoological Studies 42(2): 284-291.

Nishikawa, J., Fitzpatrick, R., Reimer, J.D., Beaman, R.J., Yamamoto, H. & Lindsay, D.J. 2011. In situ observation of Denise’s pygmy seahorse Hippocampus denise associated with a gorgonian coral Annella reticulata at Osprey Reef, Australia. Galaxea, Journal of Coral Reef Studies 13(1): 25-26. PDF Open access

Project Seahorse 2003. Hippocampus denise. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <>. Downloaded on 22 January 2012.

Reijnen B.T., S.E.T. van der Meij, L.P. van Ofwegen. 2011. Fish, fans and hydroids: host species of pygmy seahorses. ZooKeys 103: 1-26. doi: 10.3897/zookeys.103.953 PDF

Smith, R.E. 2010. The Biology and Conservation of Gorgonian-Associated Pygmy Seahorses PhD Thesis, School of Biological Sciences, The University of Queensland. 162 pp.

Smith, R.E. & Tibbetts, I.R. 2008 Mating and birth of Denise’s pygmy seahorses (Hippocampus denise) observed in the wild. Coral Reefs 27: 617. DOI:10.1007/s00338-008-0373-8

Smith, R.E., Grutter, A.S. & I.R. Tibbetts. 2012. Extreme habitat specialisation and population structure of two gorgonian-associated pygmy seahorses. Marine Ecology Progress Series 444: 195-206. Abstract

Quick Facts

CAAB Code:37282136

Biology:Males brood the eggs

Conservation:IUCN Data Deficient

Conservation:IUCN Data Deficient; CITES Listed

Depth:13–102 m

Habitat:Gorgonian sea fans

Max Size:24 mm

Species Image Gallery

Species Maps

CAAB distribution map