Nizadai (English spelling) sawtail

This marine fish belongs to the order Perciformes of the class Osteichthyes and the family Anserinidae. It is found in areas south of Chiba and Niigata prefectures, and off the coast of Taiwan. Its body is oval and well laterally compressed, reaching a total length of 40cm. Its mouth is small, with fine teeth arranged in a brush shape. It has several hard bony plates at the rear of its body, three of which are particularly prominent, giving it the nickname Sannoji. It swims in schools around rocky areas in shallow waters, and prefers to eat seaweed. The juvenile fish are called acronus, and are transparent in color and have a different body shape from the adult fish. Juvenile fish appear off the coast of Japan in early summer, living near tide pools, and gradually moving to deeper waters as they grow. It is the species that breeds furthest north out of all the fish in this family. The scales are fine and close to the body, so they can be eaten by peeling the skin like filefish, but the meat has a sea smell and is not very tasty.

Many of the closely related species are beautiful, but they must be handled with care as they have sharp bony plates (Ocean Thrush, Tenguhagi) and spines (Surgeonfish, South Sea Tangfish) on the rear of their bodies.

[Ida Sai]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

硬骨魚綱スズキ目ニザダイ科に属する海水魚。千葉県と新潟県以南、台湾の沿岸に分布。体は卵形でよく側扁(そくへん)し、全長40センチメートルに達する。口は小さく、細い歯が刷毛(はけ)状に並ぶ。体の後方に数個の硬い骨板があり、そのうちの3個がとくに顕著なのでサンノジの別名もある。浅海の岩礁域に群れをなして泳ぎ、海藻類を好んで食べる。幼魚はアクロヌルスとよばれ、体色は透明で、体形は成魚と異なっている。幼魚は日本の沿岸に初夏に現れ、潮だまり（タイドプール）付近で生活し、成長するにつれてしだいに深所に移動する。本科の魚のうち、もっとも北方で繁殖する種である。鱗(うろこ)は細かくて体に密着しているので、カワハギと同様に皮を剥(は)いで食用とするが、肉は磯臭(いそくさ)くてあまり美味でない。

　近縁種の多くは美麗であるが、体後部に鋭い骨性板（ミヤコテング、テングハギ）や、棘(とげ)（クロハギ、ナンヨウハギ）を備えているので、取り扱いには注意を要する。

［井田　齋］

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