> Subphylum Vertebrate > fishes
learn only 3 things about them ...
| They belong to the second largest family of fishes after
Young fish may look very different from adults.
can give a nasty bite. Don't touch them!
seen? These colourful fishes are sometimes seen on many of our shores. Among
the more colourful little fishes to be seen in tide pools at low tide,
wrasses are nevertheless often overlooked as they are often well hidden.
Many are active during the day, sheltering during the night in hiding
places. Small ones may burrow into sand.
What are wrasses? Wrasses belong
to the Family Labridae. This is the second largest family of fishes
after the gobies. According to FishBase:
the family has 60 genera and 500 species, found in the Atlantic, Indian
and Pacific oceans and coming in a wide range of sizes and colours.
Being such a large family, wrasses come in a wide range of sizes and
habits. They range from small fish 8cm long to large ones up to 40cm
long. The Napolean wrasse (Cheilinus undulatus) can grow to
2m long and weigh up to 180kgs!
Features: Many wrasses are brightly coloured, mostly greenish
but with patterns of blue, yellow and red. Often young fish are different
from the adults, their colours and patterns changing as they develop.
As adults, they also change colours during breeding season, the males
usually becoming more brightly coloured. Some may also change colours
to match their surroundings. This is why wrasses are sometimes difficult
Wrasse food: Most wrasses are
carnivorous predators and eat small crustaceans, snails and worms.
Most wrasses have thick lips and sharp canine teeth that stick out.
Mostly solitary hunters, they can be aggressive towards others of
their own kind. Some wrasses may also scavange. Some eat plankton,
and a few eat parasites off larger fish (see below). Many are sand
An intriguing member of this family is the Cleaner wrasse (Labroides
dimidiatus). This little wrasse performs cleaning services for
larger fishes and sea creatures, picking parasites and dead skin off
them. Marine 'clients' often form a patient queue at a cleaning station
manned by the Cleaner wrasse, allowing the little fish to enter their
mouth and gills without eating it.
Wrasse babies: Wrasses can change
their gender! Most wrasses grow to become females first. A female
can turn into a fully functional male within a few days. In some species,
each male has a harem of females. When the male dies, the largest
female changes gender and takes his place. In some species, however,
there are two kinds of males. One that is born a male (primary male),
and another that was born a female and later turned male. Primary
males can produce more sperm than those that change into males; however,
primary males usually wear the colours of a female! Mating wrasses
rise up to the water surface together, releasing eggs and sperm simultaneously.
Tuas, Apr 08
Often half buried in the sand.
Pulau Sekudu, Apr 06
Seen from above.
Pulau Sekudu, Apr 06
|Human uses: Being colourful and
lively, wrasses of various kinds are extensively harvested from the
wild for the live aquarium trade. Some large ones are harvested as
food. The Napolean wrasse (Cheilinus undulatus) is a large
fish that is being over-collected as a luxury food item for the Chinese
market. These gentle, intelligent fishes can live for 50 years and
reach up to 180kgs. Unsustainable harvesting of these fishes may doom
them to extinction.
Status and threats: None of our
wrasses are listed among the threatened animals of Singapore. However,
like other creatures of the intertidal zone, they are affected by
human activities such as reclamation and pollution. Over-collection
can also impact on local populations.
Elsewhere, harvesting of wrasses large and small may involve the use
of cyanide or blasting, which damage the habitat and kill many other
creatures. Like other fish and creatures harvested for the live aquarium
trade, most die before they can reach the retailers. Without professional
care, most die soon after they are sold. Those that do survive are
unlikely to breed.
on Singapore shores
Labridae recorded for Singapore
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
*from Lim, Kelvin K. P. & Jeffrey K. Y. Low, 1998. A Guide to the
Common Marine Fishes of Singapore.
+Other additions (Singapore Biodiversity Record, etc)
Cheilinus fasciatus (Red-banded maori
Cheilinus oligacanthus (Singapore tuskfish)
Cheilinus trilobatus=^Cheilinus trilobatus
Choerodon anchorago (Anchor
Choerodon schoenleinii (Black-spot
+Halichoeres argus (Argus wrasse)
Halichoeres bicolor (Brown-stripe
Halichoeres chloropterus (Pastel-green wrasse)
nigrescens (Diamond tuskfish)
Halichoeres gymnocephalus=^Halichoeres chloropterus
Halichoeres hoeveni=^Halichoeres melanurus
Halichoeres hyrtlii=^Halichoeres bicolor
Halichoeres javanicus=^Halichoeres nigrescens
Halichoeres leparensis=^Halichoeres argus
Halichoeres melanochir (Orangefin wrasse)
*Halichoeres purpurescens (Silty wrasse)
Halichoeres reichei=^Halichoeres nebulosus
Halichoeres scapularis=^Halichoeres scapularis
+Iniistius trivittatus (Triplebar razorfish)
+Leptojulis cyanopleura (Shoulder-spot wrasse)
+Oxycheilinus digramma (Cheek-lined Maori-wrasse)
Pteragogus sp. (Weedy
wrasse) and list of species recorded for Singapore.
Stethojulis axillaris=^Stethojulis balteata
Stethojulis interrupta (Cutribbon wrasse)
Stethojulis renardi=^Stethojulis strigiventer
Thalassoma lunare (Moon wrasse)
- A moon wrasse (Thalassoma lunare) off Lazarus Island, 20 December 2019, Adib Adris, Singapore Biodiversity Records 2019: 156 ISSN 2345-7597, National University of Singapore.
- Daisuke Taira. A Singapore record of the cutribbon wrasse, Stethojulis interrupta. 31 October 2018. Singapore Biodiversity Records 2018: 114 ISSN 2345-7597. National University of Singapore.
- Daisuke Taira. A cheek-lined Maori-wrasse in the Singapore Strait. 22 June 2018. Singapore Biodiversity Records 2018: 65 ISSN 2345-7597. National University of Singapore.
- Daisuke Taira. 29 Sep 2017. Argus wrasses at Pulau Seringat. Singapore Biodiversity Records 2017: 131-132.
- Marcus F. C. Ng. 31 Oct 2017. Singapore tuskfish at Cyrene Reef Singapore Biodiversity Records 2017: 147
- Jeffrey K. Y. Low & Koh Kwan Siong. 29 January 2016. Recent sightings of shoulder-spot wrasse in Singapore waters, Leptojulis cyanopleura. Singapore Biodiversity Records 2016: 12
- Jeffrey K. Y. Low. 21 August 2015. Pastel-green wrasse in the Singapore Strait. Singapore Biodiversity Records 2015: 114
- Jeffrey K. Y. Low. 29 May 2015. Orangefin wrasse at Pulau Satumu. Singapore Biodiversity Records 2015: 64
- Jeffrey K. Y. Low. 15 May 2015. Slingjaw wrasse in the Singapore Strait. Singapore Biodiversity Records 2015: 58
- Toh Chay Hoon, Jeffrey K. Y. Low & Debby Ng. 13 Feb 2015. Bluestreak cleaner wrasse off Big Sister Island. Singapore Biodiversity Records 2015: 27
- Tan Heok Hui & Kelvin K. P. Lim. 21 November 2014. Moon wrasse off Kusu Island, Thalassoma lunarer. Singapore Biodiversity Records 2014: 293.
- Ria Tan. 6 June 2014. New record of triplebar razorfish in Singapore, Iniistius trivittatus. Singapore Biodiversity Records 2014: 154
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
- Allen, Gerry,
Fishes of South-East Asia: A Field Guide for Anglers and Divers.
Periplus Editions. 292 pp.
- Kuiter, Rudie
H. 2002. Guide
to Sea Fishes of Australia: A Comprehensive Reference for Divers
New Holland Publishers. 434pp.
Ewald and Robert Myers. 2001. Coral
Reef Fishes of the World
Periplus Editions. 400pp.
- Lim, S.,
P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The Life
and Times of Labrador Beach. Division of Biology, School of
Science, Nanyang Technological University & Department of Zoology,
the National University of Singapore. 160 pp.
John, 1999. Battle
of the Sexes in the Animal World
BBC Worldwide, London. 224 pp.