Green Backed Guavina

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): 7; Dorsal soft rays (total): 8; Analspines: 1; Analsoft rays: 8

Found in freshwater, estuaries, inshore and mangrove (Ref. 86252). Adults occur on soft mud bottoms of rainforest creeks to elevations of at least 150 m. (Ref. 2847, 44894). They favor undercut banks for retreat. Probably has a pelagic marine larval stage (Ref. 44894).

Found in freshwater, estuaries, inshore and mangrove (Ref. 86252). Adults occur on soft mud bottoms of rainforest creeks to elevations of at least 150 m. (Ref. 2847, 44894). They favor undercut banks for retreat. Probably has a pelagic marine larval stage (Ref. 44894).

分布於印度-西太平洋區海域，包括斯里蘭卡、印尼、菲律賓、新幾內亞、海軍群島、密克羅尼西亞 (波納佩島及加羅林群島) 、澳洲與新加勒多尼亞等。臺灣分布於北部、東部及南部地區。為臺灣2008年發現的新紀錄種，臺灣同時也是本種魚分布的北界。

中小型魚類，不具食用經濟性。

第1背鰭：Ⅵ；第2背鰭：Ⅰ/ 8。臀鰭：Ⅰ/ 8；胸鰭：19~20。縱列鱗 57~63；背鰭前鱗 38~39。體延長，身體前部呈圓筒形，後則逐漸側扁。背緣、腹緣微微隆起，尾柄較長。頭中大，吻端鈍，形狀略扁平；頭後高而側扁，其頭寬大於頭高，短於頭長；無感覺管孔。頰部微凸，具數列感覺乳突線。眼小，居上位。體被細小櫛鱗。體背灰白色至茶褐色；體側灰褐色至黃褐色，另具10-12條細長的黑褐色縱紋。眼後有兩條黑色線紋，上方一條延伸至鰓蓋後緣。胸鰭基部有兩個黑色大斑：尾鰭基部另具灰褐色斑駁。(林沛立編寫)

主要生活於溪流、河川的中下游，或河口區域。通常活動於石礫灘底質的瀨區，屬於底棲性魚類。偏肉食性，主要以小型魚類、甲殼類和水生生物為食。

The greenback guavina (Bunaka gyrinoides) is a species of fish in the family Eleotridae that inhabits fresh, marine, and brackish waters in estuaries and mangrove swamps from Sri Lanka to Micronesia and Australia. This species grows to a length of 34 cm (13 in), though most do not exceed 15 cm (5.9 in). This species is the only known member of its genus.