You’re standing at the seafood counter, staring at a row of salmon filets, trying to pick the best one. They all kind of look the same, right? Pinkish-orange, sitting on a bed of ice, little price tags stuck in front of them. You grab one that looks fine, toss it in the cart, and move on with your life.
Big mistake. Because if you’d looked a little closer, you might have noticed something on that filet that should’ve made you put it right back down. There are a handful of dead giveaways that a piece of salmon has gone south — and one of the worst is a white, filmy residue coating the surface of the raw fish. That’s not moisture. That’s not fat. That’s bacteria breaking down your dinner before you even get it home.
Let’s talk about what to look for, what to avoid, and how to stop wasting $20 a pound on fish that belongs in the trash.
That White Film Is Not Your Friend
Here’s the thing that trips people up: there’s a white substance that shows up on salmon when you cook it, and that one is totally harmless. It’s called albumin — a natural protein that coagulates and pushes to the surface when heat is applied. It looks kind of crusty and weird, but it’s safe and completely edible. Some chefs actually use it as a visual cue that the fish is done.
But a white, slimy, or filmy coating on raw salmon? Completely different story. That milky residue means bacteria have already started colonizing the surface and breaking down the fish. It’s one of the clearest signs of spoilage, and no amount of seasoning or high-heat cooking is going to fix what’s already gone wrong at a cellular level. If you see it at the store, walk away. If you see it on salmon you already bought and brought home, throw it out.
Dark Spots And Gray Flesh Tell The Same Story
Color is probably the easiest thing to check, and most people do glance at it — they just don’t know what they’re looking for. Fresh wild salmon should be a deep red to vibrant orange. Farmed salmon tends to be lighter pink. Either way, the color should be consistent throughout the filet.
Brown or black patches? That’s oxidation. The fish has been exposed to air for too long and started to deteriorate. A grayish tint across the flesh? It’s old. The bright pigment in salmon fades as the fish sits around, so gray salmon is tired salmon. And if you see discoloration around the edges — darkening, drying, cracking — that filet has been sitting in the case way too long.
One color-related trick worth knowing: if a piece of farmed salmon looks too bright, almost fluorescent, that could indicate dye additives. Some producers add synthetic pigments to make farmed fish look more like wild-caught. Real color has a natural warmth to it. Fake color looks like someone ran it through an Instagram filter.
Give It The Touch Test Before You Buy
If you’re buying from a counter where you can interact with the fish (or if you’re at home deciding whether to cook what’s in the fridge), press your finger gently into the flesh. Fresh salmon should feel firm and springy. It should bounce right back when you push into it.
If it feels mushy, sinks in and stays there, or feels like it’s about to fall apart — that fish is done. Same deal with a slimy or sticky surface. Run your hand across the filet. Your hand should glide easily. If it sticks or you feel a slippery coating, bacteria have moved in and set up shop. These texture changes mean the proteins have broken down past the point of safe eating, even if you cook it to a high temperature.
Also look at the muscle fibers. Fresh salmon has tight, connected layers of flesh. If you see gaps between those layers — a condition called gaping — it usually means the fish was mishandled, stored at the wrong temperature, or has started to fall apart from age. None of those are things you want to eat.
Your Nose Knows More Than You Think
People get weird about smelling fish at the store, like it’s somehow embarrassing. Get over it. Your nose is the most reliable spoilage detector you own. Fresh salmon should smell like almost nothing — a faint hint of the ocean, maybe, but that’s it. It should smell neutral and clean.
If you open the package and get hit with a strong fishy smell, that’s already a problem. If it smells sour, like it’s turning, that’s worse. And if there’s any whiff of ammonia — that sharp, chemical-like smell — the fish has been decomposing for a while. Ammonia is a byproduct of protein breakdown. By the time you can smell it, the salmon is well past its prime.
Here’s what people don’t realize: that “fishy” smell everyone associates with seafood is actually a sign of aging. Truly fresh fish barely smells like anything. If you’ve been buying salmon that reeks of the ocean, you’ve been buying old salmon.
Frozen Salmon Has Its Own Red Flags
Frozen salmon can be a great option — sometimes even fresher than the “fresh” stuff at the counter, which may have been previously frozen anyway. But frozen fish comes with its own set of problems to watch for.
The biggest one is freezer burn: white, dried-out patches on the surface that happen when the fish wasn’t wrapped tightly enough before freezing. The moisture escapes, the texture changes, and you end up with tough, papery spots that taste like nothing. It won’t necessarily make you sick, but it’ll make for a lousy dinner.
Also check for excessive ice crystal formation on the surface. That usually means the fish went through temperature fluctuations — thawed slightly and refroze, maybe more than once. Each cycle degrades the quality. According to the USDA, raw frozen salmon is best used within three to eight months. After that, quality drops off fast.
When you thaw frozen salmon, do it in the refrigerator overnight. Never on the counter. Counter-thawing lets the outer layer warm up into the bacterial danger zone while the inside is still frozen, and that’s a recipe for food poisoning.
You Might Not Even Be Getting Real Salmon
This is the part that really makes you mad. Oceana, a marine conservation group, ran a study collecting 82 salmon samples from restaurants and grocery stores across Virginia, Washington, D.C., Chicago, and New York during winter months. Forty-three percent were mislabeled. Nearly half.
Restaurants were the worst offenders by a wide margin. Grocery stores fared better, but still not perfectly. The fraud gets worse in winter months because wild salmon season runs from roughly mid-May through September. So that “fresh wild-caught” salmon you ordered at a restaurant in January? There’s a real chance it’s farmed, or it’s a different species entirely, or it was illegally caught Russian salmon relabeled as Pacific.
An earlier Oceana study in 2013 tested 384 samples and found only 7 percent were fraudulent. The winter study’s 43 percent rate tells you exactly when the scam artists go to work. There are currently no traceability requirements that follow a fish from the boat to your plate, which makes the whole system easy to game.
The best defense? Ask where the fish came from. Ask if it’s been previously frozen. Look at the price — wild salmon typically runs $15 to $25 per pound. If you’re seeing “wild-caught” for significantly less, be suspicious. And if someone is selling you fresh wild salmon in December, they’re probably lying.
Whole Fish Tells You Even More
If you ever get the chance to buy a whole salmon, you get extra clues that filet buyers miss. The eyes should be bright, clear, and slightly bulging. Sunken or cloudy eyes mean the fish is old. The gills should be a rich, vibrant red — not faded, brown, or dull. These are the first things to deteriorate, so they’re like a freshness alarm system built right into the fish.
The skin should look shiny and silver, not dried out or peeling. If you can touch the fish, run your hand along the body. It should feel smooth and slightly slippery in a natural way — not coated in slime.
What Happens If You Eat Bad Salmon
Eating spoiled salmon isn’t just unpleasant — it can land you in serious trouble. Food poisoning from bad fish can cause vomiting, diarrhea, fever, and abdominal cramps. Symptoms can start within hours of eating it and stick around for days. For pregnant women, young children, older adults, and anyone with a compromised immune system, the consequences can be life-threatening.
Bacteria like Listeria and Salmonella thrive on improperly stored fish. Toxins produced by bacterial growth can survive cooking, too — so don’t think cranking up the oven will save a questionable piece of fish. If it smells off, looks off, or feels off, it’s not worth the gamble. Toss it.
How To Keep Your Salmon Fresh Once You Buy It
Make salmon the last thing you put in your cart at the grocery store. You want to minimize the time it spends at room temperature. Get it into the refrigerator as soon as you walk through the door. Store it at 40°F or below, and plan to cook it within one to two days.
If you’re not going to use it that quickly, freeze it immediately. Wrap it tightly in plastic wrap or foil, then put it in an airtight bag with the date written on it. Cooked leftovers last three to four days in the fridge.
And always — always — check the sell-by date on packaged salmon. It’s there for a reason. Combine that with a good look, a quick sniff, and a gentle press, and you’ll never bring home a bad filet again.
