Acentrogobius caninus (Valenciennes 1837)

Characterized by pale grey body with five diffuse brown saddles along back; midside with 4-5 diffuse brown blotches; head and body with scattered white spots; presence of diagnostic greenish patch behind upper edge of operculum; rounded caudal fin; longitudinal scale series 25-26; scales absent on head except upper half of opercle and predorsal fully scaled; mainly ctenoid body scales; depth of body 5.3 in SL (Ref. 90102).

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): 6 - 7; Dorsal soft rays (total): 9 - 10; Analspines: 1; Analsoft rays: 9

Occur along coastlines and in estuaries and harbors. Usually found in brackish tidal waters. Feed on invertebrates.

Occur along coastlines and in estuaries and harbors. Usually found in brackish tidal waters. Feed on invertebrates. Found to contain tetrodotoxin (TTX) and anhydrotetrodotoxin (anh-TTX) which causes paralytic food poisoning (Ref. 54777). Marketed fresh in Mekong delta (Ref. 12693).

分布於印度-西太平洋區海域，由馬達加斯加至日本。臺灣分布於西部海域。

小型魚類，不具漁業價值。

第1背鰭：Ⅵ；第2背鰭：Ⅰ/ 11~12。臀鰭：Ⅰ/ 9~10；胸鰭：18~20。縱列鱗 29~31。體延長，前部成亞圓筒形，後部較側扁，尾柄略長。頭中大，側扁。吻略短而圓鈍。眼間隔較窄小。口裂大，斜裂，口裂可達眼中部的下方。唇肥厚。鰓裂略小，延伸未達前鰓後緣。體被中大型的櫛鱗，頭背側及胸部、腹部被鱗。第一背鰭以第3棘較長。臀鰭的起點位於第二背鰭第2軟條的下方。尾鰭呈長圓形。體呈黃綠色，頭側和體側具亮綠色和紅色小點。體側正中有5個較大的紫黑色斑塊，排成一縱行。背側有4~5不規則的紫黑色橫斑與體側斑塊相間排列。眼後方到第一背鰭起點間具2條灰黑色橫帶。第一背鰭上部黃色，下部淺紅色，有2行由紫色斑點組成的縱帶紋，最後面的鰭處具1較大紫斑；第二背鰭邊緣紅色，中部黃色，下部淺棕色，具3縱行紫色斑點；臀鰭淺藍色，邊緣灰黃色，中部具1條黃色縱紋，近基部處有2~3縱行紅色小點；胸鰭基部有兩個紫色小斑，肩胛部有1個藍綠色圓斑；腹鰭藍灰色；尾鰭黃棕色，近邊緣處紅色，中部具1條黃色寬橫帶，其餘部份具4~5橫行藍色和紫色相間排列的小斑點。虎齒細棘鰕虎(/Acentrogobius caninus/)及虎齒鰕虎(/Yongeichthys caninus/)為其同種異名。(林上智、林沛立編寫 2012/10)

暖水性沿岸小型魚類，生活於河口汽水水域、沙岸、紅樹林及沿海沙泥地的環境。耐鹽性較廣，但不能在純淡水中生存。食肉性，以底棲動物、小型魚類、小型無脊椎動物、有機碎屑等為食。為體內含有河豚毒素(tetrodotoxin, TTX)的鰕虎魚類之一，以內臟最高，其次為生殖腺、頭部、皮膚及肌肉。為安全起見，應避免食用此魚。

Acentrogobius caninus, also known as the tropical sand goby or green-shouldered goby, is an amphidromous benthopelagic species of fish in the family Gobiidae.

It is endemic throughout the Indo-West Pacific and found in marine, fresh, and brackish water. It is recognisable by its grey body with brown markings across its body, as well as the distinct dark green spot above its pectoral fins.

Enters rivers (Ref. 4343).