Bulbnose Unicornfish

Description: Characterized by grey shading to yellowish grey on ventral parts; area below hump on back densely spotted with black; broad pale blue margin on blackish dorsal fin; caudal fin with broad submarginal blackish zone; large bulbous snout and hump on back; caudal peduncle with pair of bony plates, each with forward projecting point; greatest depth of body 2.2 (subadult)-3.0 in SL (Ref. 90102).

Dorsal spines (total): 5; Dorsal soft rays (total): 27 - 30; Analspines: 2; Analsoft rays: 26 - 28

An uncommon species (Ref. 9710) found in shallow mouths and seaward reefs. Often seen in small groups. Probably feeds on fleshy benthic algae.

Inhabits coral reefs (Ref. 37792). Feeds on leafy or fleshy algae and zooplankton (Ref. 37792). Found singly or in small groups (Ref. 37792).

fisheries: minor commercial; price category: medium; price reliability: very questionable: based on ex-vessel price for species in this family

廣泛分布於印度-太平洋水域，西起非洲東部，東至薩摩爾，北至日本南部，南至澳洲大堡礁及新加勒多尼亞。台灣目前分布於東部離島。

一般以流刺網、延繩釣或潛水鏢魚法等捕獲。觀賞及食用兼具。剝皮後，煮薑絲湯，肉質鮮美。尾柄上骨質盾板非常銳利，易傷人，處理時需小心。

體呈長橢圓形而側扁；尾柄部有二個盾狀骨板，各有一個龍骨突。頭小，隨著成長，在眼前方之額部逐漸突出而形成瘤狀突起，且背部亦會隆起。口小，端位，上下頜各具一列齒，齒稍側扁且尖銳，兩側或有鋸狀齒。背鰭及臀鰭硬棘尖銳，分別具V棘及II棘，各鰭條皆不延長；尾鰭截平，上下葉緣不延長如絲。體呈灰色，腹面灰黃色，瘤狀突起的背面及其後方體側具大片污斑及污點，有時不顯著；胸鰭與尾鰭均具黑緣。

主要棲息於較淺的礁區海域，單獨或成小群活動，棲息深度在3-20公尺，較少見到。以葉狀藻、肉狀藻及動物性浮游生物為食。

Naso tonganus is a tropical fish found in coral reefs in the Pacific and Indian Oceans. It is commonly known as the bulbnose unicornfish, hump-nosed unicornfish, humphead unicornfish, or the humpnose unicorn. It is of value in commercial fisheries.