January, 2021 | Sushiblog－Sushiuniversity

What is Shusseuo?

During the Edo period, samurai would change their names at Genpuku (coming-of-age ceremony and career stages. Following this tradition, fish that are called by names as they grow older/larger are called “shusseuo (出世魚)”, are considered lucky and are used in cooking to celebrate milestones in life.

Shusseuo doesn’t just change in name, they also change in taste. The bigger the body, the more fat. However, young fish also have their own delicious, refreshing taste unique to their age. For example, using the young fish for deep-frying and fatty fish as sashimi is an interesting way to put it.

In addition to fish commonly referred to as “syusseuo,” there are other fish whose names change as they grow. According to “A Study of Japanese Fish Names,” there are 82 species of fish whose names change as they grow. Bluefin tuna (Maguro) and Greater amberjack (Kanpachi) are representative examples. Maguro changes from “komaji” to “meji” to “maguro” to “oomaguro.” Kanpachi changes from “mojaco” to “shiwoko” to ‘akahana’ to “kanpachi.”Fish such as konoshiro, sawara, unagi, sake, and koi are not considered “syusseuo.” It is not the case that all fish whose names change as they grow are classified as “syusseuo.” Rather, these are fish whose taste improves as they grow, undergo minimal changes over time, and were highly valued in eras when preservation and transportation technologies were not yet developed.

Incidentally, opinions are divided on whether to call Maguro “Shusseuo.” Maguro is also called “Meji” or “Chubou” when it is small, and its name changes as it grows. Fishermen distinguish between different stages of Maguro before it becomes an adult fish, but when it is sold in stores, even if it is slightly small, it seems that people tend to trust the name ‘Maguro’ and do not treat it as a fish that has “made it.”

A good representative fish of shusseuo is the yellowtail (Buri). Its name changes as it grows and there are various forms of their names depending on the region. In the Kanto region, it changes from Wakashi (15-20cm) to Inada (30-40cm) to Warasa (60cm) and then to Buri (80cm or greater). It is said to be most delicious at 40 cm or longer and even if the body is plump, inada often has little fat.

Even if the name is the same, depending on the region, it may be referring to a different size. For example, inada is a fish up to 40 cm in Kanto but in Tohoku and Tokai, it refers to small fish of 15-20 cm. Further, although it is not related to its growth, those caught in Tohoku during summer are called “ao”. In Toyama, they are called “gan” and “gando”.

Finally, the changing names of fish demonstrate the breadth of culture. We should cherish this local diversity present in the names of our fish that capture the abundant food culture and importance of the seasons.

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We hope this information will be helpful.

Revision date: August 8, 2025

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What is Artificial caviar?

Caviar refers to salted sturgeon ovaries but in many European countries, caviar is also used as a generic term for fish roe. In its home of Russia, roe is generally called “ikura” and caviar specifically refers to black fish roe.

Caviar is one of the world’s three major delicacies and can command different prices depending on the type of sturgeon (egg size). It is ranked in the order: Beluga, Oscietra and Sevruga, all of which come from the Caspian Sea. Beluga from the Caspian Sea is designated as an endangered species and international trade is prohibited by the Washington Convention. Its population is very small and it does not lay eggs until 20 years into its lifespan, so the resource has yet to recover. This has brought the market price of Beluga up to around USD $400 for just 50 g.

What is the substitute for caviar?

Lumpfish roe is sold as a substitute for caviar. The size of each egg is about 2 mm in diameter and it is colored with squid ink. This gives it a taste and appearance similar to caviar. The market price is an astonishing USD $5 per 50 g.

The main ingredients of Lumpfish caviar are as follows:

　Lumpfish roe
　Salt
　Sugar
　Thickening agent
　Sodium benzoate
　Coloring

What is artificial caviar?

Artificial caviar is significantly cheaper than genuine caviar. It’s low in fats, lower in calories and healthier than the real thing. It is already a big hit in the U.S. The size of the eggs is a little larger than authentic caviar and the skin is thicker but most people would tell you the texture and taste is much the same. There has also been a decrease in sturgeon, and there is no sign that its price will fall in the future. The challenge is meeting the global demand through a combination of farmed caviar which has become a more stable supply in recent years, with the ever-dwindling wild caviar. The market price is reasonable at around USD $10 for 50 g.

There is a way to tell the difference between real caviar and fake caviar.

First, place the caviar on a cracker. Fake caviar (made of Lumpfish roe) has added color, and this color will bleed onto the cracker within about 30 minutes. However, the color will not transfer to the cracker from real caviar.

The main raw ingredients of artificial caviar are as follows:

　Sea urchin extract
　Oyster extract
　Gelatin
　Dextrin
　D-sorbitol
　Trehalose
　Gelling agent
　Seasoning
　Coloring

Finally, seafood with a high price, unfortunately, results in substitutes, counterfeits, and artificial products. Masquerading a fake as the real thing can result in a large profit. I will tell you that it is difficult to trick a middleman who serves professional sushi chefs or restaurants. Therefore anyone in Japan who uses seafood like this, does it knowingly, which makes the crime even worse.

What is Izumidai?

When you see “tai” on the menu at a conveyor belt sushi restaurant, it’s very likely that is not “madai” (Red sea bream). It’s a competitive industry where these conveyor belt restaurants have no problem using a variety of imitation or replacement fish if it means they can cut costs. In any case, the purpose for using different types of fish without even considering farmed cheap madai, is to further reduce costs.

First on the list is Nile tilapia. This fish was introduced from Egypt to rivers throughout the world as food in 1962. While it was farmed in large quantities in Japan, especially in Kagoshima, from the 1990s, production rapidly declined with the stagnant prices of farmed madai. However, they are extremely fertile and proliferate naturally, and started living in the thermal regions and the rivers where warm wastewater flow throughout Japan.

The commonly used names for this is “izumidai” or “chikadai”. While izumidai (Nile tilapia) is a freshwater fish, it was likely named after “tai” (sea bream) because of the similarities in appearance. In Taiwan, it is considered to be so similar in appearance and taste, that it is called “Taiwanese sea bream”. It is a popular fish for consumption on a global scale with high production and distribution volume.

However, even though has “sea bream” in the name, it is not actually related to the sea bream at all.

As an aside, at least 90% of the tilapia found in the U.S. is imported. Most of those imports come from China. It’s often said that they are raised on a large volume of antibiotics and pesticides, and they are kept fresh using high amounts of chemicals. It’s best to avoid eating it if possible. The tagline they give it is “Sushi grade tilapia is a high quality, firm fish with a mild, clean taste perfect for sashimi and sushi applications” You’ll be hard-pressed to even find kaiten sushi restaurants using this in Japan. In addition, it would never be used at restaurants that describe themselves as Edomae Sushi.