sponges text index | photo index
Phylum Porifera
Melted chocolate sponges
Chondrilla australiensis*
Family Chondrillidae
updated Feb 2020
Where seen? This rubbery sheet is commonly seen on our Northern shores, coating rocks and stones near the mid-water mark. People often carelessly step on them, not realising that they are animals.

Features: Thin layer encrusting small areas 15cm sometimes large areas 1m or more. Texture smooth rubbery glossy. They coat coral rubble, stones and boulders, as well as artificial walls and structures. Tiny holes (0.1cm) with a membranous lip are scattered on the surface. The holes can barely be seen when submerged, and not obvious when the sponge is out of water. It really looks like melted chocolate when it's exposed at low tide! Shades of grey, brown, greenish grey and black.

Often mistaken for an ascidian.

Many creatures are often found living on them, including synaptid sea cucumbers and tiny shrimps. Sometimes tiny sea anemones are found in the middle of the ascidian. But it's not certain whether the anemone settled into the ascidian, or the anemone was there first and the ascidian grew around it.

Tiny sea anemone
Changi, Jun 05

With synaptid sea cucumbers.
Changi, Jun 05

With synaptid sea cucumbers.
Tuas, May 05

Pulau Semakau, Aug 08
Tiny holes with a membranous lip.

Lazarus, Apr 12

Tiny holes with a membranous lip.

Sisters Island, Jan 12

Tiny holes with a membranous lip.

Species are difficult to positively identify without dissection and examination of internal parts.
On this website, they are grouped by external features for convenience of display.

Melted chocolate sponges on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Pasir Ris Park, Jan 20
Photo shared by Nurulhuda on facebook



  • Lim Swee Cheng, Nicole de Voogd and Tan Koh Siang. 2008. A Guide to Sponges of Singapore. Singapore Science Centre. 173pp.
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