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Phylum Chordata > Subphylum Vertebrate > fishes
Mojarra
Family Gerreidae
updated Sep 2020

Where seen? These little silvery fishes with dark diagonal bars is often seen at low tide on many of our shores, in sandy areas near seagrasses, reefs and rubble. Sometimes in groups of many small individuals with small fishes of other species. This fish has a widespread distribution in the Indo-Pacific.

What are Mojarras? Also called Silver-biddies or Silver bellies, they belong to Family Gerridae (some place them in the Family Ambassidae). According to FishBase: The family Gerreidae has 8 genera and 40 species. They are found in most tropical seas. The Common mojarra is the most commonly seen of the family on the intertidal.

Features:
Those seen about 5-10cm, can grow to 25cm. Body slender, long and silvery. Head with scales but with a smooth upper surface. The tail fin is deeply forked. Dorsal fin single with long and blackish tip and not deeply notched. Juveniles have 7-8 dusky diagonal bars which disappear as they grow older.

Sometimes confused with Perchlets that have a deeply notched dorsal fin, that Mojarras lack. More on how to tell apart small silvery fishes.

Pulau Tekukor, May 10

Chek Jawa, Oct 11

Pulau Semakau, Aug 05

Dorsal fin single continunous (not notched) with blackish tip.
What does it eat? It has a very protractile mouth which points downwards when extended. It sucks up a mouthful of sand with the protractile mouth and sorts out edible small bottom-dwelling animals, before spitting out the debris and sand.

Human uses: It may be sold fresh in local markets and is also ground up and used as fish meal or fed to ducks.

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

Common mojarras on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores


Tanah Merah, May 09
Photo shared by James Koh on his flickr.

East Coast-Marina Bay, Oct 15
Photo shared by Loh Kok Sheng on flickr.

Berlayar Creek, Oct 15
Photo shared by Marcus Ng on facebook.


St. John's Island , Apr 12
Photo shared by Loh Kok Sheng on his blog.

Pulau Hantu, Jun 24
Photo shared by Tammy Lim on facebook.


Pulau Semakau (East), Jul 24
Photo shared by Richard Kuah on facebook.


Terumbu Pempang Tengah, May 11
Photo shared by Rene Ong on facebook.

Raffles Lighthouse, Nov 16
Photo shared by Loh Kok Sheng on facebook.

Pulau Salu, Apr 21
Photo shared by Toh Chay Hoon on facebook.

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

  Family Gerreidae
  Gerres abbreviatus=*Gerres erythrourus (Deepbody mojarra or silver-biddy)
Gerres argyreus
Gerres filamentosus
Gerres kapas=*Gerres oyena
Gerres limbatus
Gerres macrosoma=*Gerres oblongus
Gerres oyena
(Common mojarra or silver-biddy)
Gerres punctatus=*Gerres filamentosus

Links

References

  • 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.
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