jellyfish text index | photo index
Phylum Cnidaria > various classes | jellyfish
Mangrove jellyfish
Acromitus sp.
Family Catosylidae
updated Sep 2025
Where seen? This energetic little jellyfish is sometimes seen in large numbers near mangrove, e.g., at the mouth of mangrove streams, and in estuarine seagrass meadows on our Northern shores.

Features: Bell about 6-8cm in diameter. Each fat sausage-like oral arm has a long 'tail'. Moves in short bobs as it energetically contracts its small bell.

Status: It is listed as Vulnerable at 2024 in the Singapore Red Data Book.

Sungei Buloh Wetland Reserve, Feb 09
Photo shared by Brandon Chia

Pulau Ubin, Apr 09

Chek Jawa, Apr 08

Mangrove jellyfishes on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores


Chek Jawa, Dec 12
Photo shared by Loh Kok Sheng on flickr.

Bloom of Mangrove jellyfish (Acromitus sp.)

Pasir Ris mangroves, Dec 10.

mangrove jellyfish from SgBeachBum on Vimeo.


Acknowlegement
With grateful thanks to Dr Michael N Dawson of the University of California, Merced for identifying this jellyfish.

Links
  • Checklist of Cnidaria (non-Sclerectinia) Species with their Category of Threat Status for Singapore by Yap Wei Liang Nicholas, Oh Ren Min, Iffah Iesa in G.W.H. Davidson, J.W.M. Gan, D. Huang, W.S. Hwang, S.K.Y. Lum, D.C.J. Yeo, May 2024. The Singapore Red Data Book: Threatened plants and animals of Singapore. 3rd edition. National Parks Board. 663 pp
  • Uwe Will & Iffah Iesa. River jellyfish, Acromitus hardenbergi, at Sungei Buloh. 30 November 2017. Singapore Biodiversity Records 2017: 156-157 ISSN 2345-7597. National University of Singapore.
  • The Scyphozoan website by Dr Michael N Dawson: lots of info about jellyfishes in Class Scyphozoa.
links | references | about | email Ria
Spot errors? Have a question? Want to share your sightings? email Ria I'll be glad to hear from you!
wildfactsheets website©ria tan 2008