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This species is distinguished by the following characters: body very deep, compressed, with a strongly humped back; body depth 1.7-1.9 times in standard length; mouth pointing downward when protracted; gill rakers short and fleshy, less than 1/2 length of corresponding gill lamellae, total gill rakers on first gill arch 18-22; head and breast scaleless; tubed scales on lateral line 61-66. Colour of adults, back greyish, belly silvery and many parallel close-set faint bars on back; usually a dark brown saddle on caudal peduncle; axil of pectoral fins grey to black; margin of soft dorsal fin black; both caudal-fin lobes with broad dusky margins; pectoral, pelvic, and anal fins colourless to yellowish. In juveniles (5-7 cm TL), thin, closely arranged, grey vertical lines descending from back to about midheight; membrane between anal-fin spines conspicuously yellow; posterior margin of caudal-fin lobes pale yellow and dusky; other fins hyaline; snout dotted black (Ref. 47581).

Amphidromous. Refers to fishes that regularly migrate between freshwater and the sea (in both directions), but not for the purpose of breeding, as in anadromous and catadromous species. Sub-division of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.Characteristic elements in amphidromy are: reproduction in fresh water, passage to sea by newly hatched larvae, a period of feeding and growing at sea usually a few months long, return to fresh water of well-grown juveniles, a further period of feeding and growing in fresh water, followed by reproduction there (Ref. 82692).

Dorsal spines (total): 8; Dorsal soft rays (total): 15 - 16; Analspines: 3; Analsoft rays: 14 - 15

Found in river mouths and muddy inshore areas. Sometimes enters freshwater (Ref. 2847). Between February and May, adult less abundant in the estuary (Ref. 4959). Feeds on zooplankton and benthic invertebrates (Ref. 11889).

Found in river mouths and muddy inshore areas (Ref. 2847, 37816), often in mangrove areas (Ref. 48635). Adults are coastal inhabitants found on soft bottoms, usually between depths of 10-70 meters. Juveniles are commonly found in mangrove estuaries and tidal creeks, sometimes entering the lower reaches of freshwater streams (Ref. 44894). Adults move in schools. Frequently ascend into freshwater reaches of rivers (Ref. 12693). Active by day (Ref. 12693). Feed on polychaetes, small crustaceans, small fishes (Ref. 30573) and worms (Ref. 12693). Important food fish in the tropics (Ref. 4376). Caught near the bottom with bottom trawls, set nets, push nets, dip nets, and beach seines. In Indian waters, schools near the surface during April-May when caught with drift gill nets. Larger specimens sorted for human consumption and marketed fresh or dried-salted, but surplus fish used to feed ducks, converted to fishmeal, or discarded (Ref. 47581).

fisheries: minor commercial; aquaculture: commercial; price category: high; price reliability: questionable: based on ex-vessel price for species in this genus

分布於印度-西太平洋水域。台灣以西部、西南部砂泥底沿岸、河口及內灣為主。

以流刺網或岸邊灘釣均有可能捕獲。為鰏科中體型較大的魚種，味美且肉較多，紅燒、煮湯皆宜。以夏季為盛漁期。

體卵圓形而側扁，背部之輪廓較腹部為凸。眼上緣具二鼻後棘。口小，可向下方伸出；上下頜僅一列細小齒；下頜輪廓深凹；吻端截平，眶間隔凹入。頭部不具鱗；體被圓鱗，除了胸部無鱗；腹鰭具腋鱗，背鰭及臀鰭具鞘鱗；側線明顯，延伸至尾鰭基部。背鰭第二棘稍延長，體高約為其長的1.9-2.5倍。體背灰色，體側銀白。體側上半部另具排列緊密但不顯明的垂直黑帶。尾柄背部另具一條灰褐色斑紋。吻端具黑點。背鰭軟條之鰭緣黑色；胸鰭灰色而具暗色緣；尾鰭後緣灰色到暗黃色。

主要棲息於沿岸砂泥底質水域，大多棲息於淺水域，水深約在1-40公尺之間，有時會進入深水域，有時會進入河口區。一般在底層活動覓食，肉食性，以底棲生物為食。

Leiognathus equulus, the common ponyfish is a species of marine ray-finned fish, a ponyfish from the family Leiognathidae. It occurs in brackish and marine waters from East Africa to Fiji in the Indian and western Pacific Oceans, Red Sea and Persian Gulf.