Sourcing Fish for Sushi — What Chefs Actually Look For

The question I get asked most often about making sushi at home isn't about technique or equipment. It's about fish.

Where do you buy it? How do you know if it's safe to eat raw? What does sushi-grade actually mean? These are the right questions — and the answers are simpler than most people expect.

Here's what I've learned working in professional Japanese kitchens in London, handling fish every single service.

How Professional Kitchens Source Fish

At the restaurants I've worked in, fish comes from specialist suppliers who deliver directly to the kitchen. Where I work now at Kiyoto, fresh salmon arrives every single day. At my previous kitchen it was three times a week. The frequency depends on volume — busier kitchens need more frequent deliveries to maintain freshness.

The moment a delivery arrives, the head chef checks it immediately. The first thing checked is temperature — the fish must arrive at 0–2°C. If it's arrived warmer than that, something went wrong in transit and the quality is already compromised.

This is the professional standard. For home cooks, the principle is the same — temperature is the first indicator of quality.

How to Judge Fish Quality — What I Actually Check

After years of handling fish professionally, quality assessment becomes instinctive. Here's what to look for:

Smell

This is the most reliable indicator and the one most people get wrong. Fresh fish does not smell fishy. That strong fishy smell is the sign of fish that is past its best — it's the smell of decomposition beginning.

Fresh fish smells clean. Like the sea. Mild, almost neutral. If you pick up a piece of fish and get an immediate strong smell, put it down.

Texture

Fresh fish should feel firm and tight when you press it gently. The flesh should spring back. Fish that is going off becomes soft and slimy — the texture breaks down as the proteins degrade. If the surface feels slippery or the flesh doesn't hold its shape, it's not fresh enough for raw consumption.

Appearance

The colour should be vibrant and consistent. Salmon should be a deep, even orange-pink. Tuna should be a rich red. Any browning, discolouration, or dull patches are warning signs. The surface should look moist and slightly glossy — not dry or dull.

The Truth About "Sushi Grade" Fish

Here's something important that most guides don't tell you: "sushi grade" is not a regulated term in the UK. Any fishmonger or supermarket can label fish as sushi grade without meeting any specific standard. The label means nothing legally.

What actually matters is freshness and handling. The best approach for home cooks is to find a fishmonger you trust — ideally one that supplies restaurants — and simply ask them directly: "Is this fish suitable for eating raw?" A good fishmonger will give you an honest answer.

Fresh vs Frozen — What Japanese Chefs Taught Me

This surprised me when I first learned it from Japanese chefs at Eat Tokyo: frozen fish is often better and safer for sushi than fresh fish.

The reason is parasites. Wild fish — certain tuna, some white fish — can carry parasites that are harmful if eaten raw. Freezing fish to -20°C for at least 24 hours kills these parasites, making the fish safe to eat raw. Many professional sushi kitchens freeze fish specifically for this reason before serving it as sashimi.

However, not all fish needs to be frozen. Farmed salmon — which is the most common sushi fish — is raised in controlled environments with monitored feed. The parasite risk is much lower, which is why fresh farmed salmon can go straight to the plate without freezing.

So the rule isn't "fresh is always better than frozen." The rule is: know your fish, know its source, and understand the risk.

How to Handle Fish at Home

At work, when a whole fish delivery arrives, the process is immediate: clean and gut the fish, wash with cold water, dry thoroughly with a clean cloth, then prepare for storage or immediate use. Speed and cleanliness matter — the fish should never sit around at room temperature.

At home, the same principles apply:

• Keep fish cold at all times — 0–2°C in your fridge
• Use it the same day you buy it for raw consumption
• Store on ice if possible, or on the coldest shelf of your fridge
• Keep it covered and away from other foods
• Dry it with kitchen paper before slicing — moisture affects the cut

Where to Buy Fish for Home Sushi in the UK

In order of preference:

1. Japanese Supermarkets

In London — Japan Centre, Atariya, Tazaki Foods. These stock fish specifically sourced for raw consumption and the staff understand what you're buying it for. Outside London, look for any Asian supermarket with a fresh fish counter.

2. Specialist Fishmongers

Find a fishmonger that supplies restaurants. They handle high volume, turnover is fast, and quality standards are higher than supermarkets. Ask specifically if the fish is suitable for eating raw — they'll tell you honestly.

3. Online Fish Suppliers

Several UK online suppliers deliver sashimi-quality fish overnight on ice. The Fish Society, Fin & Flounder, and Atariya all ship nationally. More expensive but reliable quality.

4. Supermarkets — With Caution

Major supermarkets do sell salmon suitable for sushi — particularly skin-on fresh farmed salmon. Check the use-by date carefully and use it the same day. Avoid pre-packaged sushi packs — make your own with fresh fish.

Quick Reference

Good fish handled well makes everything else easier. Start with quality ingredients and the technique follows naturally. 🔪