Chocolate Surgeonfish

Body uniformly brown to dark brown; caudal fin pale in color (snow white in live fishes). Small, dark spot below and adjacent to axil of pectoral fin. Anterior gill rakers 15-18; posterior 14-16. Snout length 7.9 to 8.2 times in SL. Least depth of caudal peduncle 2.2 to 2.5 times in head length (Ref 9808).

Dorsal spines (total): 9; Dorsal soft rays (total): 23 - 26; Analspines: 3; Analsoft rays: 23 - 26

This occasionally schooling species occurs in steep outer reef slopes and drop-offs (Ref. 1602). Feeds on zooplankton, particularly large gelatinous forms, and on fish eggs and crustaceans (Ref. 13550).

This occasionally schooling species occurs in steep outer reef slopes and drop-offs (Ref. 1602, 48637). Benthopelagic over coral and sand (Ref. 58302). Feeds on zooplankton, particularly large gelatinous forms, and on fish eggs and crustaceans (Ref. 1920).

aquarium: commercial

廣泛分布於印度-太平洋區，西起非洲東部，東至馬貴斯及杜夕群島，北至日本，南至拉帕。台灣北部、東北部及東部離島有分布。

一般以流刺網、延繩釣或潛水鏢魚法等捕獲。體型較小，且較少見，一般作為觀賞用魚。尾柄上骨質盾板非常銳利，易傷人。

體呈橢圓形而側扁。頭小，頭背部輪廓隨著成長而略凸出。口小，端位，上下頜各具一列扁平齒，齒固定不可動，齒緣具缺刻。背鰭及臀鰭硬棘尖銳，分別具XI棘及III棘，各鰭條皆不延長；胸鰭近三角形；尾鰭彎月形，隨著成長，上下葉逐漸延長。體一致為橄欖褐至藍灰色，但在胸鰭腋下具一大黑斑，背鰭基底末緣具一小黑斑。除尾鰭白色外，各鰭與體同色；尾柄棘溝緣為黑褐色。

主要棲息於外礁陡坡區。群游性。以浮游動物，如甲殼類以及魚卵等為食。

Acanthurus thompsoni is a tropical fish found in the Pacific and Indian Oceans. It is commonly known as the Thompson's surgeonfish. It is commercial in aquarium use.

This occasionally schooling species occurs in steep outer reef slopes and drop-offs at depths of 4 to over 75 m (Ref. 1602). It feeds on zooplankton, particularly large gelatinous forms, and on fish eggs and crustaceans.