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Freshwater Fishes of Singapore

Freshwater Fishes of Singapore

A forest stream located in the Central Catchment Nature Reserve beside a public trail.

Singapore's freshwater ecosystems have undergone significant changes over time. Historically, over 50 species of freshwater fishes were recorded in our waterways, but many have since disappeared due to habitat destruction, competition from invasive species, pollution, and other human-induced pressures. Today, only 36 native freshwater fish species remain, many of which are restricted to our nature reserves, with a few having a wide distribution across various habitats. 

MacRitchie Reservoir is full of invasive species but a few native ones manage to thrive!

Unfortunately, a majority of our large water bodies such as reservoirs, quarry lakes and canals are dominated by invasive species which number to be about 123 species and counting (Tan et al., 2020). Sights of fishes like Peacock Basses, Motoro Stingrays and Tilapias are abundant in the mentioned habitats. While our threatened native species are currently residing in the nature reserve away from those open waters, the invasive species are knocking on their doors and must be monitored to lessen their impacts on our already fragile freshwater ecosystems.

One of Singapore's few quarry lakes, unfortunately dominated by invasive species.

The Central Catchment Nature Reserve is home to a majority of our native freshwater species, which several can only be found in small pockets there such as the Nee Soon Swamp Forest. The Nee Soon Swamp Forest is Singapore's last primary freshwater swamp forest and is the only home to a few fishes such as the Hasselt's Leaf Catfish (Silurichthys hasseltii) and the Buff-backed Spiny Eel (Macrognathus maculatus).

This unique ecosystem also supports a variety of other rare and threatened flora and fauna, including two of Singapore’s endemic freshwater crabs, the Reticulated Swamp Crab (Parathelphusa reticulata) and the Johnson's Freshwater Crab (Irmengardia johnsoni). The diverse habitats within this treasured part of the Central Catchment Nature Reserve include acidic, blackwater forest streams with tannin-stained waters and low pH, characteristic of swamp forests, as well as fast-flowing, sandy, and clear forest streams.

An acidic forest stream in the Nee Soon Swamp Forest. (Photograph taken with NParks)

Although currently lower in fish diversity, the Bukit Timah Nature Reserve's varied elevation gives way to habitats such as rocky hill streams and quarry lakes, alongside forest streams and small catchments. It is home to several threatened species such as the endangered Sunda Leaf Fish (Nandus nebulosus). The loss and degradation of some habitats led to the extinction of fishes like the Malayan Clown Barb (Barbodes dunckeri), which was described from the reserve. 

However, the reserve still remains ecologically significant as its water bodies support an array of Singapore's biodiversity beyond fishes such as the endemic Singapore Freshwater Crab (Johora singaporensis).

The jungle falls trail at Bukit Timah Hill is a good example of a rocky hill stream.

Outside of the nature reserves, native species can also be found in habitats such as drains and ponds, especially in open country sides, cemeteries and more. These habitats are usually stagnant and low in oxygen, allowing only adaptable species to thrive. Such fishes include gouramis, bettas and snakeheads, which have the ability the breathe air! Singapore has some well-known species such as the Three-spot Gourami (Trichopodus trichopterus) and the Croaking Gourami (Trichopsis vittata).

For the future of our freshwater ecosystems, conservation is essential to the protection of such habitats, alongside the management of invasive species and pollution. Spreading awareness to the public is also key so that future generations can appreciate our precious freshwater biodiversity for years to come.

Want to find out more about our native freshwater fishes? Here is a list of the 36 species still extant in Singapore in reference to the Singapore Red Data Book (Third Edition):

Family
  • Common Name (Species name) (Conservation status in Singapore)

    LC - Least Concern, NT - Near Threatened, VU - Vulnerable, EN - Endangered CR - Critically Endangered
Cyprinidae

Danionidae

Cobitidae

Nemacheilidae

Bagridae

  • Long-Whiskered Catfish (Mystus gulio) (LC)
  • Dwarf Bumblebee Catfish (Pseudomystus leiacanthus) (CR)

Siluridae

Akysidae

  • Longnose Little Warty Catfish (Parakysis longirostris) (CR)

Clariidae

Synbranchidae

Mastacembelidae

Zenarchopteridae

Aplocheilidae

Gobionellinae

  • Roundhead Stream Goby (Eugnathogobius siamensis) (CR)
  • Broadhead Stream Goby (Pseudogobiopsis oligactis) (VU)

Nandidae

Anabantidae

  • Climbing Perch (Anabas testudineus) (LC)

Osphronemidae

Channidae

*All information will be updated when updated references and observations appear!

*All photographs belong to the authors of this blog.

References
  • Li, T., Loh, Y.X., Lim, W., Nyanasengeran, M., Low, B.W., Tan, H.H., Yeo, D.C.J., & Cai, Y. 2019. The fish fauna of Bukit Timah Nature Reserve, Singapore. Gardens’ Bulletin Singapore, 71(Suppl. 1): 557–573. DOI: 10.26492/gbs71(suppl.1).2019-21. 
  • Li, T., Chay, C.K., Lim, W.H., and Cai, Y. 2016. The fish fauna of Nee Soon Swamp Forest, Singapore. Raffles Bulletin of Zoology, Supplement No. 32: 56–84. Retrieved from http://zoobank.org/urn:lsid:zoobank.org:pub:39FA639F-84C2-4C66-90AE-F3A64DEF3D0D.
  • Lim, K.P. and Ng, K.L. 1990. A Guide to the Freshwater Fishes of Singapore. Singapore Science Centre.
  • National Parks Board (NParks). Freshwater Fishes. Retrieved from https://www.nparks.gov.sg/nature/species-list/freshwater-fishes.
  • Tan, H.H., Lim, K.P., Liew, J.H., Low, B.W., Lim, R.B.H., Kwik, J.T.B., & Yeo, D.C.J. 2020. The non-native freshwater fishes of Singapore: an annotated compilation. Raffles Bulletin of Zoology, 68: 150–195. DOI: 10.26107/RBZ-2020-0016.

 


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