Black Triggerfish

Description: Characterized by dark blue to purplish blue overall color with pale blue margins; teeth red; strongly elevated anteriorly, second dorsal and anal fins; front of eye with deep groove; slightly convex dorsal profile of head, ventral profile strongly convex; upturned mouth, protruding chin; prolonged two upper teeth, visible when mouth is closed; around seven longitudinal rows of small spines on posterior half of body; lunate caudal fin, prolonged lobes in large adult (Ref. 90102).

Distinct pairing (Ref. 205). Only females tend the eggs but both parents keep guard (Ref. 116451).

Dorsal spines (total): 3; Dorsal soft rays (total): 33 - 36; Analspines: 0; Analsoft rays: 28 - 31

Occurs in current-swept seaward coral reefs. Usually forms aggregations and feeds on zooplankton as well as sponges. Juveniles associated with isolated patches of rubble or crevices with proper-sized shelter holes (Ref. 1602).

Inhabits reef channels or along slopes that are subject to strong currents (Ref. 48637). Occur in current-swept seaward coral reefs. Usually form aggregations and feed on zooplankton as well as sponges (Ref. 9770). Juveniles associated with isolated patches of rubble or crevices with proper-sized shelter holes (Ref. 1602). Oviparous (Ref. 205). Form large schools to feed on zooplankton (Ref. 48637). Also taken by drive-in nets (Ref. 9770). Marketed fresh or dried-salted. Minimum depth reported taken from Ref. 30874. Popular aquarium fish (Ref. 37816).

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

Odonus niger (Rüppell)

The adductor mandibulae is somewhat reduced in size, particularly sections A 2α and A 2β. A 3 is also reduced, but A 1α and A 1β are better developed than in the other balistids examined.

The cutaneous portion of the protractor hyoidei is well developed, with some fibers of the more dorsal portions originating from the dorsal three branchiostegal rays. The sections of the hyohyoidei abductores from the second to fifth rays are much reduced. The horizontal and vertical subdivisions of the sternohyoideus are present, and the pharyngoclavicularis externus is poorly developed.

Only the ventral fibers of levator externus V are developed, and these grade into an aponeurotic sheet dorsally, which fuses to the outer face of the midregion of levator IV. Both levatores interni are poorly developed, and transversus dorsalis II is as for B. vetula. The protractor pectoralis is well developed. The arrector ventralis pelvicus is as for R. aculeatus, the movable portion of the pelvis being much reduced. The inclinator analis of the first anal fin ray appears to consist of two sections, and the transversus caudalis is small.

Summary of Balistidae

In the balistids, there is some variation in the relative development of the sections of the adductor mandibulae, and minor differences in the size of the levator arcus palatini. The development of the cutaneous portion of the protractor hyoidei differs, as does the relative size of the sections of the hyohyoidei abductores. Two subdivisions of the sternohyoideus are usually present (one vertical and the other horizontal). The extent to which levator externus V develops varies, and transversus dorsalis II may or may not have fibers arising from the midline behind its main origin on the parasphenoid. There is some variation in the posterior region of the arrector ventralis pelvicus, and the transversus caudalis is usually poorly developed.

While there is more variation in the Balistidae than in either of the two preceding families, it is usually of a minor nature and relatively unimportant at the level of analysis to be used here.

Myological Descriptions of Representative Monacanthids

The general body outline of representatives of this family is given in Figure 4. Out of the 22 genera recognized by Fraser-Bunner (1941a), species representing 10 genera have been examined. Body form is basically conservative, and similar to balistids, although there are numerous exceptions such as the long snouted Oxymonacanthus and the tremendously elongate Anacanthus. The scales are spinose. The dorsal spines, of which there are normally two (the second being able to lock the first in position), vary in position from behind the eye to the anterior snout region. The pelvis may be in evidence externally, as in balistids, or may simply be a movable strut of bone completely covered by skin. Locomotion is mainly by undulations of the soft dorsal and anal fins, turning being achieved by the pectoral fins and flexion of the body. The caudal fin does not seem to be used at all in Pseudalutarius (Wickler, 1962), although it may be brought into play in escape movements. The teeth are much the same as in the balistids, but the general body plan is less robust.

The food of monacanthids is rather varied. Some species are totally herbivorous, others omnivorous, while yet others ingest primarily animal matter. They are usually found around coral reefs and on the sea-grass flats of tropical waters, although some species do occur in colder regions.

分布於印度-太平洋區，西起紅海、非洲東岸，東至社會及馬貴斯群島，北至日本南部，南至澳洲大堡礁及新加勒多尼亞。台灣除西部及北部外，皆有分布。

通常以陷阱法、潛水或流刺網捕獲，以生鮮或醃製於市場出售，或以其可愛的模樣而常被飼養於水族館中，供人欣賞，是極受歡迎之魚種。

體稍延長，呈長橢圓形， 尾柄短。口稍上位，齒紅色，上頜有一對極長之犬齒。眼前有一深溝。除口緣唇部無鱗外，全被骨質鱗片；頰部亦全被鱗；鰓裂後有大型骨質鱗片；尾柄鱗片具小棘列。背鰭兩個，基底相接近，第一背鰭位於鰓孔上方，第I棘粗大，第II棘則細長，第III背鰭棘明顯；背鰭及臀鰭軟條軟條前端較長，向後漸短；尾鰭彎月形，上下葉延長為絲狀。體色一致為藍黑色；頭部顏色較淺，帶少許綠色；吻緣藍色，有藍紋自吻部延伸至眼部。

主要棲息於受洋流沖刷的向海礁區，一般被發現於水深40公尺內的水域，通常隨動物性浮游生物而做覓食遷移，尤其是海綿幼體；幼魚則生活於片礁區及或礁石洞穴。

The Redtoothed triggerfish (Odonus niger) is a triggerfish of the tropical Indo-Pacific area, and the sole member of its genus. Some other common names include blue triggerfish, redfang triggerfish, redtoothed filefish, and Niger triggerfish.

Occurs in current-swept seaward coral reefs. Usually forms aggregations and feeds on zooplankton as well as on sponges (Ref. 9770). Juveniles associated with isolated patches of rubble or crevices with proper-sized shelter holes (Ref. 1602). Also taken by drive-in nets (Ref. 9770). Marketed fresh or dried-salted.