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Mojarras


Mojarras and silver-biddies are the common names used for the members of Gerreidae family. They often occur near the bottom in coastal waters of most tropical seas. They are mainly saltwater fishes but can also occur in brackish water and sometimes freshwater. They are recognized as small silvery fishes with terminal and highly protractile mouth. Their scales are large, obvious but deciduous.

Mojarras are often found in coastal lagoons and estuaries with sandy or muddy bottoms near mangroves. They can be found in school, small group or singly. They feed on small invertebrates gleaned from the bottom by taking up mouthfuls of substrate and expelling sand and debris.

There are 7 genera and about 51 species of Gerreidae worldwide. Malaysia has 2 genera and about 9 species.



Scientific Name: Gerres erythrourus  (Bloch, 1791)
English Name: Deep-bodied Mojarra, Deep-body Silver-biddy
French Name: Blanche elévée
Mandarin Name | 鱼类中文名: 胶把 (Jiāo bǎ), 短钻嘴鱼 (Duǎn zuān zuǐ yú)
Local Malay Name: Ikan Kapas-kapas, Kekapas, Kapas Laut, Kapas Sungai
Thai Name | ชื่อสามัญภาษาไทย: ปลาดอกหมากครีบสั้น (Plād xk h̄māk khrīb s̄ận)
Local Hokkien: Ka Pak
Main Identification Features: Dorsal and anal fin spines strong, particularly second anal fin spine. Caudal fin strongly forked but short, and lobes broadly rounded without pointed tips. Dorsal fin edged with black. Trailing edge of caudal fin dusky. Anal and pelvic fins yellowish.
Size: Maximum total length about 30 cm, commonly to 20 cm.
Habitat and Ecology: Coastal waters, to 40 m depth. Form schools on sandy bottoms. Feeds on zooplankton, worms, bivalves, crustaceans and small fishes.






Scientific Name: Gerres filamentosus  Cuvier, 1829
English Name: Whipfin Mojarra, Whipfin Silver-biddy, Long-rayed Mojarra
French Name: Blanche fil
Mandarin Name | 鱼类中文名: 胶把 (Jiāo bǎ), 曳丝钻嘴鱼 (Yè sī zuàn zuǐ yú)
Local Malay Name: Ikan Kapas-kapas, Kekapas, Kapas Laut, Kapas Filamen
Thai Name | ชื่อสามัญภาษาไทย: ปลาดอกหมากกระโดง (Plād xk h̄māk kradong)
Local Hokkien: Ka Pak
Main Identification Features: Second dorsal-fin spine laterally compressed, produced into a filament. Anal, caudal, pectoral, and pelvic fins dusky hyaline, tips of anal fin, lower lobe of caudal and pelvic fins white.
Size: Maximum total length about 30 cm, commonly to 15 cm.
Habitat and Ecology: Shallow coastal waters, estuaries and rivers, to 50 m depth. Often found in schools on sandy bottoms. Feeds on small organisms such as crustaceans, polychaetes, and foraminiferans on sand or muddy-sand bottoms.






Scientific Name: Gerres oyena  (Forsskål, 1775)
English Name: Common Silver-biddy, Blacktip Silver Biddy, Longtail Silverbiddy, Oceanic Silver Biddy, Shining Silver-belly, Slender Silver Belly
French Name: Blanche commune
Mandarin Name | 鱼类中文名: 胶把 (Jiāo bǎ), 银钻嘴鱼 (Yín zuān zuǐ yú)
Local Malay Name: Ikan Kapas-kapas, Kekapas, Timah, Senolong, Kapas Laut
Thai Name | ชื่อสามัญภาษาไทย: ปลาดอกหมากยาว (Plā dok h̄māk yāw)
Local Hokkien: Ka Pak
Main Identification Features: Body slender, depth less than 40% of standard length. Scales on lateral line 35 to 39 to base of caudal fin. Anal fin base short. Spinous dorsal fin with an indistinct dusky patch and very narrow dusky distal margins on upper membranes between spines. Pectoral fins reaches beyond level of anus. Caudal fin deeply forked with long lobes.
Size: Maximum total length 25 cm, commonly to 15 cm.
Habitat and Ecology: Coastal and estuarine waters, on sand or sand and mud, to 50 m depth. Feeds by sifting small invertebrates from mouthfuls of substrate.






Scientific Name: Pentaprion longimanus  (Cantor, 1849)
English Name: Longfin Mojarra, Longfin Silver-biddy
French Name: Blanche à pagaies
Mandarin Name | 鱼类中文名: 胶把 (Jiāo bǎ), 长臂钻嘴鱼 (Cháng bì zuǎn zuǐ yú)
Local Malay Name: Ikan Kapas, Kapas-kapas, Kekapas, Kapas Kaca
Thai Name | ชื่อสามัญภาษาไทย: ปลาดอกหมากครีบยาว (Plād xk h̄māk khrīb yāw)
Local Hokkien: Ka Pak
Main Identification Features: Anal fin base longer than base of the soft portion of dorsal fin. Colour silvery, with a mirror-like stripe from snout to caudal peduncle.
Size: Maximum total length almost 20 cm, commonly to 10 cm.
Habitat and Ecology: Coastal muddy-sand bottoms, to 70 m depth. Often form large schools. Feeds on small benthic invertebrates.