hydroid text index | photo index
Phylum Cnidaria > Class Hydrozoa
Stinging hydroid
awaiting identification*
updated Mar 2020

Where seen? This colony of tiny animals can be common on some offshore Northern shores, forming alarming large colonies. Sometimes also seen on our Southen shores. It grows on coral rubble or hard surfaces.

Features: Colonies can be 20-30cm wide. Made up of black thin branches (4-20cm long) with feathery side branches. Some look like clumps of grass with long, sparsely branched or unbranched stems (10-20cm). Others are bushier with stems that have more branches and fern-like structures (1-3cm long).

Macrorhynchia philippina has white feathery branches that pack a powerful sting.

Bushy fern-like stinging hydroids.
Tuas, Apr 05

Grass-like pale stinging hydroids.
Beting Bronok, Aug 05

Out of water
East Coast Park, May 16
Burning feathers : These hydroids can inflict painful burning stings that take a long time to heal. Even a slight brush against it on bare skin will cause an immediate fiery reaction, raising painful welts that itch for a long time.

How to stay safe: Wear covered shoes and long pants to cover all skin exposed to water. Do not touch hydroids.

Tiny tentacles.
Changi, Aug 12

Tiny tentacles.
Changi, Aug 12

Black bits may be reproductive structures.
Beting Bronok, Aug 15
Hydroid friends: Despite their stings, sometimes, tiny animals can be found living among hydroids. These include tiny shrimps and other crustacea and nudibranchs. Squid egg capsules have also been seen laid on these hydroids!

Tiny shrimp.
Beting Bronok, Jun 10

Tiny amphipods often found in large
numbers in this hydroid.
Tuas, Apr 05

Coils of eggs laid by a slug?
Changi, Aug 12

Squid egg capsules.
Changi, May 17

Squid egg capsules.
Beting Bronok, Jun 12

A nudibranch (Lomanotus vermiformis)
Changi Carpark 1, May 21
Photo shared by Toh Chay Hoon on facebook.

*Species are difficult to positively identify without close examination.
On this website, the animals are grouped by external features for convenience of display.

Stinging hydroids on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Tanah Merah, May 14
Photo shared by Loh Kok Sheng on his blog.

Tanah Merah, Jun 16
Photo shared by Loh Kok Sheng on flickr.

St John's Island, Sep 07
Photo shared by Loh Kok Sheng on flickr.

Lazarus, Mar 20
Photo shared by Vincent Choo on facebook.

Pulau Tekukor, Nov 20
Photo shared by JIanlin Liu on facebook.

Small Sisters Island, Aug 20
Photo shared by Loh Kok Sheng on facebook.

Pulau Jong, Apr 15
Photo shared by Neo Mei Lin on her blog.

Terumbu Semakau, Aug 17
Photo shared by Jonathan Tan on facebook.

Pulau Semakau North, Jul 15
Photo shared by Russel Low on facebook.

Raffles Lighthouse, Aug 06

Pulau Salu, Apr 21
Photo shared by Jianlin Liu on facebook.



  • Gosliner, Terrence M., David W. Behrens and Gary C. Williams. 1996. Coral Reef Animals of the Indo-Pacific: Animal life from Africa to Hawaii exclusive of the vertebrates Sea Challengers. 314pp
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