You sit at the sushi counter. The chef places a piece of nigiri in front of you. It's glistening, simple. You eat it. It's delicious. But what was it? Beyond "tuna" or "salmon," there's a whole ocean of nuance. Japanese fish cuisine isn't just about eating raw fish; it's a disciplined study of seasonality, texture, flavor profiles, and the subtle art of enhancement. Having spent years talking to chefs at Tsukiji (and now Toyosu) and countless meals, I've learned that most guides miss the point. They list fish but don't explain why a master chef treats a piece of kohada with reverence and serves salmon as a casual option. Let's fix that.
What You'll Learn in This Guide
The Main Cast: Understanding Key Japanese Fish
Forget alphabetical lists. Think of them in categories based on their role in the meal.
The Heavy Hitters (Akami-mono)
These are the lean, red-fleshed fish. Flavor is clean, texture is firm.
- Maguro (Bluefin Tuna): The king. But here's the non-consensus part: everyone obsesses over otoro (fatty belly). The real test of a sushi chef is their akami (lean red meat). A great piece of akami should have a deep, meaty, almost iron-like richness, not be dry or stringy. The best is often aged a few days. Chutoro (medium-fatty) is the sweet spot for many.
- Katsuo (Bonito/Skipjack Tuna): The workhorse. Often seared (tataki) which unlocks an incredible smoky, savory aroma. Fresh katsuo in early summer (初鰹, hatsu-gatsuo) is a celebrated delicacy, lean and punchy. The autumn version (戻り鰹, modori-gatsuo) is fatter. It's also the base for dashi broth.
The Silver Skins (Hikari-mono)
Fish with shiny, blue-silver skin. They're often cured or marinated because they can be stronger flavored. This is where technique shines.
- Aji (Japanese Horse Mackerel): My personal favorite for value. Incredibly flavorful—sweet, oily, with a clean finish. Served with grated ginger and scallions. If it tastes fishy, it's not fresh or well-handled.
- Saba (Mackerel): Famously strong. It's almost always cured in salt and vinegar (shime saba) to firm the flesh and mellow the flavor. A perfectly balanced piece is a thing of beauty—tangy, rich, and creamy all at once.
- Kohada (Gizzard Shad): The ultimate chef's fish. Tiny, with a complex, briny, slightly metallic taste. The curing process is meticulous. A single piece tells you more about a sushi shop's skill than their otoro.
The Delicate Whites (Shiromi)
White-fleshed fish with subtle, sweet flavors. They're about texture and purity.
- Hirame (Flounder/Flatfish): The texture is crisp, almost crunchy (which they call shiko). The rim of the fin (engawa) is a prized, chewy-fatty treat. Often served with a dab of citrus or yuzu kosho.
- Tai (Sea Bream/Red Snapper): The celebratory fish. Flavor is mild, elegant, slightly sweet. The texture is tender but distinct. It's a benchmark for freshness.
| Fish (Japanese / English) | Flavor Profile | Key Texture | Best Season (Japan) | Typical Preparation |
|---|---|---|---|---|
| Maguro / Bluefin Tuna | Meaty, rich, umami (akami) to buttery (otoro) | Firm (akami) to melting (otoro) | Winter (fattiest) | Nigiri, sashimi, tataki |
| Aji / Horse Mackerel | Pronounced oily, sweet, clean finish | Tender, slightly soft | Spring to Summer | Nigiri (with ginger/scallion), sashimi |
| Saba / Mackerel | Rich, oily, tangy (after curing) | Dense, creamy | Fall to Winter | Shime saba (cured), nigiri, sashimi |
| Hirame / Flounder | Very mild, delicate, slightly sweet | Crisp, firm (shiko) | Winter | Sashimi, nigiri, usuzukuri (thin slices) |
Notice I haven't mentioned salmon yet. That's deliberate. While ubiquitous globally, wild salmon (鮭, sake/shake) is traditionally cooked in Japan (grilled, in soups). The fatty, orange, raw salmon we eat today is primarily farmed Atlantic salmon from Norway, a modern introduction. It's popular for a reason—it's tasty and forgiving—but it's not part of the traditional Edomae sushi canon.
How to Pick Fish Like a Pro (It's Not Just About Freshness)
The biggest misconception? Fresher is always better. For many fish, a state of "just killed" can mean the flesh is tense and the flavor hasn't developed. Skilled chefs use aging (熟成, jukusei)—controlled refrigeration for days—to break down proteins, concentrate flavor, and improve texture. Tuna, for instance, is often aged.
So what should you look for?
At a Fish Market or Counter:
- Eyes: Clear, plump, and protruding. Cloudy or sunken eyes are a late sign.
- Gills: Bright red or pink, not brown or slimy.
- Smell: A clean, briny, oceanic scent. Any sharp, ammonia-like, or overly "fishy" smell is a hard pass.
- Flesh: Firm, elastic. Poke it gently (if allowed); it should spring back. No gaping or mushiness. For fillets, the surface should be glistening, not dried out or watery.
- Skin: For silvery fish (hikari-mono), the scales should be tight and reflective, not dull or falling off.
For Sashimi/Sushi at Home: This is critical. Do not buy regular supermarket fish. You need fish explicitly labeled "sashimi-grade" or "sushi-grade." This isn't a legal term, but it implies the fish has been handled for raw consumption: flash-frozen at very low temperatures (-20°C/-4°F or below for a specific duration) to kill parasites. Even then, you're trusting the supplier. Build a relationship with a dedicated fishmonger.
I learned this the hard way early on, using a "very fresh" sea bass from a regular market. The texture was fine, but the anxiety afterward wasn't worth it.
The Art of Preparation & The Right Way to Enjoy It
Preparation is everything. A knife skill called sogigiri (cutting against the grain) is used on tougher-fleshed fish like tuna to shorten muscle fibers, making it tender. Hikari-mono are scaled meticulously, often cured.
Now, eating it. Let's break some bad habits.
Soy Sauce Dipping: The chef seasons the rice. They often brush the fish with nikiri (a reduced, sweetened soy sauce). Dunking the nigiri rice-side-down is a crime. It makes the rice fall apart and overwhelms everything. Dip the fish corner only, lightly. Or better yet, try the first piece as the chef intended, with no extra soy.
Wasabi: It's already inside the nigiri. Adding more is fine if you love the heat, but know that it will dominate the fish's flavor.
Ginger (Gari): It's a palate cleanser, not a side salad. Eat a slice between different types of fish to reset your taste buds.
Order of eating? There's a logic: start with lighter, leaner fish (white fish, akami), move to richer, oilier ones (silver fish, toro), and finish with stronger flavors like uni or eel. But honestly, eat what you want. Just maybe don't start with mackerel.
Culture, Seasonality & Sustainability
Japanese fish culture is tied to shun (旬), the peak season. Hatsugatsuo (first bonito of spring) is celebrated in poetry. Winter yellowtail (寒ブリ, kan-buri) is fat and luxurious because it's stored energy for migration. Eating with the seasons guarantees the best flavor and texture.
Then there's sustainability. Bluefin tuna populations are a major concern. The Monterey Bay Aquarium's Seafood Watch program lists several tuna species as "Avoid." What can you do?
- Explore alternatives: Fall in love with katsuo, aji, saba, mackerel—they're often more abundant and just as delicious.
- Ask questions: Where is this from? Is it farmed or wild? Reputable restaurants should know.
- Support better practices: Look for fish certified by the Marine Stewardship Council (MSC) or from farms following Aquaculture Stewardship Council (ASC) standards.
It's not about never eating tuna, but about appreciating the whole spectrum and making conscious choices.
Your Burning Questions Answered
The journey with Japanese fish is endless. It starts with recognizing a name on a menu, evolves into tasting the difference between akami and chutoro, and maybe one day leads you to savor a perfect piece of kohada with a new understanding. It's a delicious education. Next time you're at the counter, try ordering by the Japanese name. Point to the aji. Skip the extra soy sauce. See how it changes the experience.
