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Phylum Chordata > Subphylum Vertebrate > fishes
Silver moony
Monodactylus argenteus
Family Monodactylidae
updated Sep 2020

Where seen? Seldom seen on the intertidal, but this elegant fish was showcased at the Sungei Buloh Wetlands Reserve visitor centre's aquarium. Groups of them are sometimes seen by divers at Pulau Hantu. Fishermen are also sometimes seen catching them on our shores. In the wild, they may school in large numbers in open waters, under jetties and in bays. It is also known as Diamond fish and Silver batfish.

What are moonies?
Silver moonies belong to Family Monodactylidae. According to FishBase: the family has 2 genera and 5 species. Found in schools in estuaries and near freshwater streams, in harbours and near jetties. Some species are inhabit brackish waters and may even swim far up into freshwater systems.

4-25cm. Body flattened sideways into a rhomboid shape. Adults silvery with a yellow and dusky dorsal fin and lack pelvic fins. Juveniles have pelvic fins, are more colourful with almost all yellow dorsal fin and a narrow black bar on the head through the eye and another bar over the gill cover. Some describe the juveniles as sometimes being dark, almost black, with a red tip on the dorsal fin. Being really flat, from the front, the fish looks like a stick! 'Mono' means 'one' and 'daktylos' means 'finger'.

Sometimes confused with the Batfish.

Sungei Buloh Wetland Reserve, Oct 03

Seen from the front, it resembles a stick!
Sungei Buloh Wetland Reserve, Oct 03
What does it eat? It feeds on plankton and detritus and are said to be highly territorial.

Human uses: The fish is sometimes caught by local anglers and is considered a common and popular freshwater aquarium fish.

Silver moonies on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Siloso, May 09
Photo shared by Ivan Kwan on his blog.

Family Monodactylidae recorded for Singapore
from Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.

  Family Monodactylidae
  Monodactylus argenteus (Silver moony)



  • Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore. National Council on the Environment. 163pp.
  • Allen, Gerry, 2000. Marine 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 & Fishermen New Holland Publishers. 434pp.
  • Lieske, Ewald and Robert Myers. 2001. Coral Reef Fishes of the World Periplus Editions. 400pp.
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