See Comment ‍‍ﾠ­​ㅤ

 

My Friend Works at a Fish Restaurant—He Told Me Which 10 Fish I Should Think Twice About Ordering

My friend has worked in the seafood business for years, so he has seen just about everything that happens behind the scenes in a fish restaurant. He knows which fish arrive fresh, which ones are harder to source responsibly, which varieties can contain higher levels of mercury, and which dishes may not be worth the price on the menu.

One day, while we were talking about our favorite seafood dishes, I asked him a simple question:

“If you were eating at a restaurant, are there any fish you would avoid ordering?”

His answer surprised me.

I expected him to mention one or two obscure varieties that most people have never heard of. Instead, he named several fish that I had ordered many times—and some of them were among my favorites.

Of course, that doesn't mean these fish are automatically unsafe or that nobody should ever eat them. Seafood can be a healthy and delicious part of a balanced diet. The issue is that certain species can present particular concerns depending on their size, age, origin, preparation, mercury levels, sustainability, or the way a restaurant handles them.

So, rather than treating this as a strict list of fish that nobody should ever eat, think of it as a guide to 10 types of fish you may want to think twice about when ordering at a restaurant.

1. Swordfish

Swordfish is a favorite in many seafood restaurants because it has a firm texture and a rich, meaty flavor. Unlike delicate white fish that can fall apart easily, swordfish can be grilled or seared almost like a steak.

But there is a reason my friend told me to be cautious about ordering it frequently.

Swordfish is a large predatory fish, and large, long-lived predators can accumulate higher concentrations of mercury over time. Mercury exposure is particularly important for pregnant people, young children, and others who are advised to limit high-mercury seafood.

That doesn't mean one swordfish dinner is automatically dangerous. The concern is more about frequency of consumption.

If swordfish is your favorite, you don't necessarily have to eliminate it from your diet. Instead, consider how often you're eating it and whether lower-mercury seafood could be an alternative.

2. Shark

Shark can appear on restaurant menus in different forms, sometimes marketed simply as “shark steak.”

Like swordfish, sharks are large predatory animals and may accumulate significant amounts of mercury. Some shark species are also vulnerable to overfishing, making sustainability another consideration.

There is an additional issue: consumers don't always know exactly which species they are receiving.

Because seafood labeling can vary by country and restaurant, a generic menu description may not tell you much about the fish's exact origin or species.

If you're curious about a shark dish, asking the restaurant where the fish came from and what species it is can give you more useful information than simply relying on the menu name.

3. King Mackerel

Mackerel is complicated because not all mackerel are the same.

Some varieties are nutritious, flavorful, and relatively low in mercury. However, king mackerel is a different story and is commonly included among fish that people should limit because of its higher mercury content.

This is a perfect example of why the exact species matters.

A menu that simply says “mackerel” doesn't always give customers enough information to know what they are eating.

If you're ordering mackerel, ask which type it is. Smaller species can have very different nutritional and environmental profiles from large predatory species.

4. Tilefish

Tilefish is another name that deserves some attention.

Certain tilefish populations, particularly those associated with the Gulf of Mexico, have historically been known for elevated mercury levels. Because of that, recommendations regarding tilefish can depend on the exact location where it was caught.

This is one reason the phrase “Where was the fish caught?” can be surprisingly useful when ordering seafood.

A reputable restaurant should be able to provide at least some information about the fish's origin. If staff members don't know anything about the species or source, you may want to choose something else.

Again, the point isn't that every piece of tilefish is inherently unsafe. The important factor is that species and location can matter enormously.

5. Orange Roughy

Orange roughy has a mild flavor and a delicate texture, which has made it popular in some seafood markets and restaurants.

However, there are two major reasons to think carefully before ordering it.

First, orange roughy can contain relatively high levels of mercury. Second, these fish are slow-growing and can live for decades. Their life history makes them particularly vulnerable to overfishing because depleted populations can take a long time to recover.

A fish that grows slowly and reproduces relatively late doesn't respond to heavy fishing pressure in the same way as a rapidly reproducing species.

For environmentally conscious diners, this makes orange roughy a species worth researching before ordering.

6. Atlantic Cod From Uncertain Sources

Cod is one of the world's most familiar fish. It's used in everything from fish and chips to grilled fillets and seafood sandwiches.

The fish itself isn't necessarily something you need to avoid. The bigger question is where it came from.

Some cod fisheries have experienced significant pressure over the years, and sustainability can vary considerably between fisheries.

This is an important lesson for seafood lovers: a species name alone doesn't always tell you whether a particular serving is an environmentally responsible choice.

If a restaurant provides information about the fishery, certification, or harvesting method, that's useful. When the menu gives no indication of origin, asking the server can help.

And if you're ordering cod because you want a mild, flaky white fish, there may be other responsibly sourced options available.

7. Imported Farmed Fish With Little Information About Its Source

This category is less about a specific species and more about transparency.

Farmed fish can absolutely be part of a sustainable seafood system. Aquaculture provides a significant portion of the world's seafood and can reduce pressure on certain wild populations.

However, farming practices vary.

Feed, water quality, stocking density, medication practices, environmental management, and escape prevention can all influence the environmental impact of a farmed fish operation.

That's why the phrase “farmed” doesn't automatically mean good or bad.

If you're concerned about sustainability, ask the restaurant what kind of fish it uses and where it comes from. A restaurant that takes seafood sourcing seriously will often be able to provide more information.

8. Tuna—Depending on the Species

Tuna is another fish that requires some nuance.

Some tuna species are relatively low in mercury compared with larger tuna, while others can accumulate considerably more. Large tuna can also raise sustainability concerns because different fisheries use different fishing methods.

Then there's the restaurant factor.

A menu might simply say “tuna,” without telling you whether you're getting yellowfin, bigeye, bluefin, albacore, or another species.

These aren't interchangeable from a nutritional or environmental perspective.

If you're ordering tuna regularly, learning which species you're eating can help you make more informed choices.

And if you're pregnant or otherwise advised to limit mercury exposure, it's particularly important to follow current guidance about which tuna varieties and serving amounts are appropriate.

9. Escolar

Escolar is a particularly interesting example because the issue isn't primarily mercury.

Escolar contains naturally occurring compounds called wax esters. Some people can experience gastrointestinal symptoms after eating significant amounts of escolar, including stomach cramps or oily diarrhea.

Because of this, escolar has sometimes been given misleading menu names or confused with other fish.

The problem isn't necessarily that the fish is “poisonous.” Rather, some people's digestive systems don't tolerate its natural composition well.

If you see escolar on a menu, it's worth knowing what you're ordering instead of assuming it's simply another type of white fish.

People can react differently, and the amount consumed can matter.

10. Any Fish That the Restaurant Can't Explain

This might be the most useful piece of advice my friend gave me.

Sometimes the biggest warning sign isn't a particular species at all.

It's a restaurant that can't answer basic questions about the seafood it serves.

Where did the fish come from?

What species is it?

Was it wild-caught or farmed?

How was it stored?

How long has it been on the menu?

A knowledgeable restaurant doesn't necessarily need to give you a ten-minute lecture about every fish, but staff should generally have enough information to answer reasonable questions about their seafood.

Freshness is especially important.

Fish should generally have a clean, fresh smell rather than a strong ammonia-like or unpleasant odor. The flesh should look appropriate for the species, and restaurants should follow proper refrigeration and food-safety practices.

If something about a seafood dish seems questionable, it's perfectly reasonable to ask questions or choose another option.

So, Should You Stop Eating Fish?

Absolutely not.

This is where many internet articles get carried away.

A list titled “10 fish you should never eat” sounds dramatic, but the reality is much more nuanced.

Fish can provide high-quality protein and important nutrients, including omega-3 fatty acids in many species. For many people, seafood can be a valuable part of a healthy diet.

The goal isn't to become afraid of seafood.

The goal is to become a more informed seafood consumer.

Instead of asking, “Is this fish good or bad?”, ask better questions:

What species is it?

Where was it caught or farmed?

How often do I eat it?

Does this species tend to contain more mercury?

Is it considered a sustainable choice in this fishery?

Does the restaurant appear to handle seafood properly?

Those questions can tell you much more than a viral list on social media.

What My Friend Changed About the Way I Order Fish

After hearing all of this, I realized that I had been ordering seafood based almost entirely on taste.

If something sounded delicious on the menu, I ordered it.

Now, I pay more attention to the details.

I don't automatically reject a fish because someone online says it's “bad.” Instead, I try to find out what species it is, where it came from, and whether there are any specific concerns associated with it.

I've also learned that the best choice can depend on the person.

Someone who eats seafood occasionally may have different considerations from someone who eats it several times a week. Pregnant people and young children may need to follow stricter advice concerning mercury. Sustainability-minded diners may prioritize different information than someone primarily concerned with nutrition.

There isn't one universal seafood rule that works for everyone.

The Bottom Line

My friend's advice completely changed the way I look at restaurant seafood.

Some fish that seem completely ordinary can have higher mercury levels, sustainability concerns, or other characteristics worth knowing about. But that doesn't mean every fish on this list is automatically dangerous, nor does it mean you can never enjoy them.

The smarter approach is to know what you're ordering.

Swordfish, shark, king mackerel, certain tilefish, orange roughy, some cod fisheries, particular tuna species, escolar, and seafood with unclear sourcing can all deserve additional consideration for different reasons.

At the same time, many other fish can be excellent choices, and responsible restaurants may offer plenty of options.

So the next time you're sitting in a seafood restaurant with a huge menu in front of you, don't be afraid to ask a few questions.

What species is this? Where did it come from? Is it wild or farmed? And is there another option you would recommend?

You might discover something delicious that you would never have considered—and you may also avoid ordering a fish simply because its name sounds familiar.

My friend certainly changed the way I order seafood.

And honestly, I wish someone had told me all of this sooner.