How to Buy Fish: A Chef and Dietitian's Guide

Before you look at a single fillet, look at the case itself. A well-run seafood counter tells you most of what you need to know, and a neglected one tells you to shop somewhere else.

A good case has these things in common:

• The fish sits on a thick bed of fresh ice, not a thin melting layer, and the fillets are nestled into the ice instead of resting on top of it.
• The case smells clean and briny, a little like the ocean. It should not smell like fish.
• The fillets are arranged in a single layer with space around them, and nothing is stacked or crowded.
• The display looks tidy, the ice is clean, and no liquid is pooling under the fish.
• Someone is working behind the counter who can answer a question about what came in that morning.

That last one matters more than you may think, because the person behind the counter knows which fish arrived today and which has been sitting for a few days. Most of them are happy to tell you if you ask. Try it the next time you're there and just say, "What came in freshest today?"

If the case looks neglected, the smell is strong, or nobody's around to help, buy from the freezer section instead. That isn't settling, for reasons you’ll soon see.

Once you've sized up the counter, you can check the individual piece you're considering. Five things tell you almost everything about freshness:

• The flesh looks moist and slightly translucent. Fresh fish has a wet sheen. Dull, chalky, or dried-out edges mean it's been sitting.
• The color is even, with no brown or gray patches. A little natural variation is fine, but discoloration around the edges or along the seams is a sign of age.
• The fillet holds together. Press gently with a fingertip if the counter lets you. The flesh should spring back and if your finger leaves a dent, the fish is past its prime.
• No liquid is pooling underneath. A puddle in the tray means the fish is breaking down and losing moisture.
• It smells like almost nothing. Fresh fish has a faint clean scent. That strong "fishy" smell people associate with seafood is the smell of fish starting to go bad.

A whole fish gives you two more clues. The eyes should be clear, plump, and a little domed, never cloudy or sunken, and the gills underneath should be bright red or deep pink instead of brown or slimy.

If you only remember one thing from this section, make it the smell test. Your nose is a better judge of freshness than your eyes, and it works through the plastic wrap at the self-serve case too.

This is the question we get asked most, and the answer is more reassuring than people expect. Both can be a good choice, and the difference affects your wallet and your taste preference more than your health.

Wild caught fish is caught in the ocean, a lake, or a river, while farm raised fish is grown in managed pens or tanks. That's the whole distinction, and neither one is automatically better than the other.

Here’s what the difference is:

• Wild caught fish tends to be leaner and firmer. It has a more pronounced flavor that varies by season and region. It also usually costs more, and availability comes and goes.
• Farm raised fish tends to be fattier and milder. Many people prefer this, especially anyone who says they don't like fish. It's available year-round and it's usually cheaper.
• Both deliver omega-3 fatty acids. These are the heart-healthy fats that make fish worth eating. Farmed salmon often has as much as wild salmon, and sometimes more, because of how the fish are fed.
• Farming practices vary by operation and by country. This is an environmental question more than a nutrition one.

So why does farmed fish have a bad reputation? Some of it is earned, since crowded pens can mean more antibiotics and poorly managed farms can damage the surrounding water. But the industry has changed substantially over the past decade, and responsible farming is now common enough that a blanket rule about skipping farmed fish just doesn’t hold water anymore.

A simpler approach to choosing fish works better. Buy whichever one looks freshest and fits your budget that week. If you want to weigh the environmental side, look for a certification label on the package: the Marine Stewardship Council (MSC) blue label covers wild fisheries, and the Aquaculture Stewardship Council (ASC) label covers farms. Both mean an outside group audited the operation.

Our dietitians would rather you eat farmed salmon twice a week than wild salmon twice a year. Getting fish into your regular rotation is the part that helps your heart.

Most people treat the freezer case as a backup plan, but you may want to rethink that.

A lot of fish in the fresh case was frozen at some point, thawed at the store, and set out on ice. That's what "previously frozen" means on the sign, and by law the store has to disclose it. Fish sold that way has already been through a thaw cycle and is now sitting at counter temperature, losing quality by the hour.

Fish in the freezer case is often frozen within hours of being caught, sometimes right on the boat. It hasn't thawed or been handled, and the clock hasn't started. Nutritionally it's nearly identical to fresh, because freezing doesn't damage protein or omega-3 fats in any meaningful way.

That’s why we often encourage people to buy frozen. It's cheaper and keeps for months, so you can cook it any night you want, even when you don’t have time to go to the store.

Here are a few things worth knowing when you shop the freezer case:

• Look for fillets that are solidly frozen with no soft spots and skip any package with frost or ice crystals inside, which usually means it thawed and refroze.
• Vacuum-sealed individual portions are worth the small premium because you can thaw exactly what you need.
• Check that the fillets move freely in the bag, since a frozen block stuck together points to a temperature swing somewhere along the way.
• Thaw overnight in the refrigerator when you can. If you're short on time, seal the fish in a bag and set it in cold water for 20 to 30 minutes.

If you do buy from the fresh case, ask whether it was previously frozen. This is important to know because previously frozen fish should be cooked within a day and shouldn't go back in the freezer.

Fatty fish, like salmon, sardines, herring, anchovies, and trout, have a nutritional edge and deliver the most omega-3 fatty acids. That’s why the American Heart Association recommends 2 servings of fish a week with an emphasis on those varieties.

The best fish to buy, though, is the one you'll actually eat. Below is how our dietitians approach the most common options at a grocery store.

Salmon

Salmon is the easiest fish to recommend and the one most worth learning to shop for. It's forgiving to cook, rich in omega-3s, and mild enough for people who claim not to like seafood.

When you're picking a fillet, look for deep even color and visible white fat lines running through the flesh, which are a good sign. Sockeye runs a deep red with a fuller, more assertive flavor. Atlantic salmon, which is almost always farmed, is paler, fattier, and milder. Coho sits between the two.

Buy the thickest, most even cut you can find. A fillet that tapers badly will overcook at the thin end while the thick end is still raw. Skin-on is a bonus, since the skin holds the fish together in the pan and peels right off after cooking.

Cod, Haddock, and Other White Fish

Cod suits more recipes than anything else at the counter. It's mild, flaky, affordable, and it takes on whatever you season it with, which makes it the right pick when you're feeding someone who's not a big fan of seafood.

Cod and haddock are close cousins, and you can substitute one for the other in nearly any recipe. Haddock is a little sweeter and finer-grained, while cod is a little firmer. Pollock is the budget-friendly member of the same family, and it's what most fish sticks are made from.

Look for fillets that are bright white and slightly translucent. White fish shows its age faster than salmon does, so any yellowing along the edges is a sign to pick a different piece.

Tuna

Fresh tuna steaks should be deep red or dark pink and look almost glossy. Brown edges mean the fish has been exposed to air too long. Tuna is lean and cooks fast, so buy a thick steak and pull it off the heat early.

Canned tuna deserves a mention too, because it's one of the most affordable ways to get omega-3s. Light tuna is lower in mercury than albacore, which is worth knowing if you eat it often.

Tilapia

Tilapia gets criticized, sometimes unfairly. It's very lean, very mild, inexpensive, and almost always farmed. It has far less omega-3 than salmon, so it isn't the fish to lean on if heart health is your main reason for eating seafood. As a source of lean protein that cooks in minutes, though, it earns its place, and it's a reasonable starting point for a skeptical household.

Look for fillets that are pinkish white and evenly cut, and pass on anything gray.

Whole Fish

Buying a whole fish costs less per pound, and it's the easiest way to judge freshness because nothing has been trimmed away. Check the eyes and the gills and look for skin that's shiny and firmly attached.

Ask the counter to scale, gut, and fillet it for you. They'll almost always do it at no charge, and you can take the bones home for stock if you want them. A 2-pound whole fish yields roughly 1 pound of fillet, so plan accordingly.

The American Heart Association defines a serving as 3 ounces of cooked fish, about the size of your palm. Fish loses a little weight as it cooks, so buy 4 to 6 ounces of raw fillet per person.

For a family dinner, that works out to:

• About 1 pound for 3 people, or a little more if your household eats generously.
• About 1.5 pounds for 4 people, which is the most common weeknight amount.
• About 2 to 2.5 pounds for 6 people.
• Roughly double the raw weight if you're buying whole fish, since you're paying for bones and skin.

You have more options than you might think, and the best one depends on what you're cooking.

• A dedicated fish market usually has the freshest selection and the most knowledgeable staff. If you have one nearby, it's worth a trip when you want something specific.
• The grocery store seafood counter is fine for most purposes, and the good ones turn over their inventory quickly. Ask what came in that day.
• The freezer case at any supermarket is the most reliable option week to week, and often the best value.
• Warehouse clubs sell large vacuum-sealed portions at a low price per pound, which works well if you have freezer space.
• Online seafood delivery ships flash-frozen fish directly and gives you access to species your store doesn't stock. It costs more, and it makes the most sense for a special occasion or something you can't find locally.

Whichever you choose, shop for fish last. It should go from the cold case into your cart and into your refrigerator with as little time in between as possible.

Fish has a short window of freshness, so knowing how to store it is important.

• Refrigerate fresh fish immediately and cook it within 1 to 2 days.
• Keep fish in the coldest part of the refrigerator, usually the back of the bottom shelf, and set the package on a plate to catch any drips.
• If you won't cook fish within 2 days, freeze it. Wrap it tightly, press out the air, and label it with the date. Don't refreeze fish that was sold fresh but previously frozen, or if it was thawed on the counter.
• Frozen fish keeps well for 3 to 6 months for fatty fish like salmon, and up to 8 months for lean white fish.

Cooked fish is usually good for 3 to 4 days in the refrigerator, which makes it useful for lunches. Our guide on how to store leftovers safely covers the rest of the details.

Every recipe on our site is developed and reviewed by our registered dietitians, so the nutrition numbers are ones you can trust.

Here are a few places to go next if you’re looking for inspiration:

• Our heart healthy salmon recipes collection is the biggest seafood roundup on the site, with everything from easy-to-make dishes to salmon cakes.
• These low calorie salmon dishes are the ones our readers come back to the most.
• Wondering whether salmon burgers are healthier than beef? We answered that question and the information may surprise you.
• For anyone on a weight loss medication, our GLP-1 salmon and seafood recipes are a light but protein-rich way to enjoy a meal.
• And these gluten free fish recipes are quick enough for a weeknight dinner that anyone can eat.