White flesh
Chicken grunt (Isaki)
【Nigiri sushi: Shiromi】
Chicken grunt (Isaki) is one of the fish most closely associated with summer, along with Japanese sea bass (Suzuki). Its pale pink flesh offers a delicate, refined richness with each bite, accompanied by a subtle hint of the briny flavor characteristic of coastal fish. When paired with vinegared rice, the fish’s rich umami and natural sweetness are further enhanced. In particular, Isaki caught during the tsuyu (rainy season), from June to July, is prized for its well-marbled flesh and exceptional seasonal flavor.
Generally, summer fish such as Japanese sea bass tend to have a mild, clean flavor. Isaki, by contrast, is in season from spring through summer and is characterized by its rich, fatty flavor. Many fatty fish that are in season during the summer, such as hairtail, pike conger, conger eel, and Japanese eel, have slender, elongated bodies. Isaki is unusual in having a relatively deep body while also possessing rich, fatty flesh.
Isaki is delicious both as sashimi and grilled with salt. Although juvenile fish are sometimes available during the colder months, their flesh is thinner than that of adult fish, and they have not yet accumulated sufficient fat. As a result, they are unfortunately not well suited for sushi. For this reason, ordering Isaki nigiri in winter seems to go against the seasonal sensibility that is so important in sushi culture.
【What is Isaki】
Isaki is written using a few different character combinations, “鶏魚” (which translates literally as ‘chicken fish’), “伊佐木” and “伊佐幾”. Adult Isaki grows as long as 40 cm. You can find it on the coasts of Japan where there are warm currents. In most cases, fish lose their flavor during the spawning season, but isaki maintains its flavor even when carrying eggs, so it is available to eat during its summer spawning season.
【Nutrition and Effects of Isaki】
Sea bass and horse mackerel are seasonal fish in Summer, low in fat and have a refreshing taste. However, Isaki has a high amount of fat for a Spring/Summer fish. There are fish other than Isaki that peak in Summer and have high fat content such as swordfish, conger eel, and unagi, but all of these fish have slender bodies such, so fish like Isaki is rare. As it has a large amount of fat, it is also rich in DHA and EPA, which can delay the progression of arteriosclerosis and prevent lifestyle-related diseases.
Also called Threeline grunt.
【Related contents】
List of White flesh fish (Shiromi)
(Revision date: October 13, 2026)