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Ordering fish at a restaurant often feels like one of the healthiest decisions you can make.
You sit down, scan the menu, and see grilled salmon, tuna steaks, fried seafood, snapper, swordfish, or some beautifully prepared daily catch. Compared with a heavy burger or a rich pasta dish, fish can seem like the obvious choice.
But there’s another side to ordering seafood that many diners don’t consider.
The question isn’t simply whether a fish tastes good.
It can also be about where the fish came from, how it was caught, how it was stored, how frequently you eat it, whether it is sustainably sourced, and whether certain species naturally contain higher levels of contaminants such as mercury.
That doesn’t mean fish is unhealthy.
Far from it.
Fish can provide high-quality protein, omega-3 fatty acids, vitamin D, vitamin B12, selenium, and other valuable nutrients. For many people, seafood can be an excellent part of a balanced diet.
The problem is that not every fish is equally appropriate for every diner or every situation.
Some species are relatively high in mercury.
Some restaurant dishes may be heavily fried or covered in rich sauces.
Some menu names are vague enough that you don’t really know which species you’re ordering.
And some seafood choices raise sustainability concerns.
So rather than thinking of this as a list of fish that are “bad,” it’s more useful to think of it as a list of fish that may deserve extra attention when you’re eating out.
Here are 10 fish you may want to think twice about—and some alternatives that can make ordering seafood easier.
## 1. Swordfish
Swordfish is popular for a reason.
Its thick, meaty texture makes it feel more like a steak than a delicate fish fillet. It’s often grilled, seared, or served with vegetables and a lemon-based sauce.
But swordfish is also one of the species that can contain relatively high levels of mercury.
Mercury accumulates in fish over time, particularly in larger predatory species that eat other fish.
Swordfish are large predators and can therefore accumulate more mercury than many smaller fish.
For an occasional restaurant meal, this doesn’t automatically mean you need to panic.
But people who are pregnant, trying to become pregnant, breastfeeding, or feeding young children should pay particularly close attention to official seafood guidance concerning high-mercury species.
### What to choose instead
Try salmon, trout, sardines, or another lower-mercury seafood option.
These alternatives can provide valuable nutrients while generally presenting less concern about mercury exposure.
## 2. Shark
Shark can appear on menus in some coastal restaurants, seafood establishments, and specialty eateries.
Like swordfish, sharks are large predatory fish.
Because they occupy a high position in the marine food chain and can live for years, some shark species can accumulate substantial amounts of mercury.
Another issue is sustainability.
Shark populations can be vulnerable to overfishing, and different species face very different conservation circumstances.
That means the question isn’t simply whether shark tastes good.
It is also whether you know what species you’re eating and where it came from.
### What to choose instead
If you’re looking for a firm, meaty fish, ask about sustainably sourced salmon, mahi-mahi, or responsibly sourced cod.
And if shark is on the menu, don’t be afraid to ask the restaurant what species it serves and where the seafood was sourced.
## 3. King Mackerel
Mackerel can be confusing because the word covers several different fish.
Some types of mackerel are nutritious choices and can be excellent sources of omega-3 fatty acids.
King mackerel, however, is a high-mercury species and is generally placed among fish that people should limit or avoid depending on their circumstances.
This is an excellent example of why the exact species matters.
A menu that simply says “mackerel” doesn’t necessarily give diners enough information to make an informed decision.
If you’re concerned about mercury, ask which type of mackerel the restaurant serves.
### What to choose instead
Atlantic mackerel is generally a different story and can be a nutritious choice when appropriately sourced.
Salmon and sardines are also excellent alternatives if you’re specifically looking for omega-3-rich seafood.
## 4. Tilefish
Tilefish has a mild flavor and firm texture, which can make it attractive to restaurant chefs.
But “tilefish” is another name that requires caution because mercury levels can vary substantially depending on where the fish was caught.
Certain tilefish from the Gulf of Mexico have historically been associated with particularly high mercury levels.
That doesn’t mean every fish labeled tilefish is identical.
Geographic origin matters.
This is a good reminder that seafood safety isn’t always as simple as memorizing a list of species.
### What to choose instead
Ask the restaurant where its tilefish was caught.
If the answer isn’t clear, choose a lower-mercury option such as salmon, trout, cod, or haddock.
## 5. Bigeye Tuna
Tuna is one of the most popular fish served in restaurants.
It’s found in sushi.
It’s served as a seared steak.
It’s placed in salads.
It’s used in sandwiches.
And it’s often considered a healthy, protein-rich choice.
But tuna isn’t one single species.
Different types of tuna can have dramatically different mercury levels.
Bigeye tuna, in particular, is a species that can contain relatively high mercury levels.
That’s especially relevant for people who eat tuna frequently.
A single meal isn’t necessarily the issue.
Repeated exposure is more important when considering mercury intake.
### What to choose instead
Ask what kind of tuna is being served.
If you’re eating sushi, you can also consider lower-mercury options such as salmon, depending on the restaurant and your personal dietary needs.
If you love tuna, variety matters.
Rather than eating the same high-mercury species repeatedly, rotate seafood choices.
## 6. Orange Roughy
Orange roughy is a mild, white-fleshed fish that has appeared on restaurant menus for decades.
It can be prepared in many different ways and doesn’t have an especially strong fish flavor.
But there are two important reasons to think twice before ordering it.
First, orange roughy can contain relatively high levels of mercury.
Second, the species has historically raised sustainability concerns because orange roughy can live for a very long time and mature relatively slowly.
Those characteristics can make populations vulnerable when fishing pressure is high.
### What to choose instead
Cod, haddock, pollock, or responsibly sourced trout can be useful alternatives.
If sustainability is important to you, ask the restaurant whether its seafood is responsibly sourced.
## 7. Imported Farmed Salmon of Unclear Origin
Now here’s a fish that may surprise people.
Salmon is often considered one of the best seafood choices.
And it can be.
Salmon is rich in omega-3 fatty acids and provides plenty of protein.
But the source still matters.
“Salmon” doesn’t tell you whether it is wild-caught or farmed, where it came from, or how it was produced.
Farmed salmon isn’t automatically bad.
In fact, responsibly managed aquaculture can be an important part of feeding a growing population.
The issue is transparency.
If a restaurant simply lists “salmon” without providing any sourcing information, diners may have difficulty knowing what they’re getting.
### What to choose instead
Don’t automatically reject farmed salmon.
Instead, ask the restaurant what type of salmon it serves and where it comes from.
If sustainability is a priority, look for restaurants that clearly explain their seafood sourcing.
## 8. Escolar
Escolar is one of the more unusual fish on this list.
It has a rich, buttery texture that some diners love.
But that richness comes from its naturally high concentration of certain indigestible wax esters.
For some people, eating escolar can cause gastrointestinal symptoms, including diarrhea and stomach discomfort.
That’s why escolar has earned a reputation as a fish diners should approach cautiously.
It may also appear under different names on menus, depending on the establishment.
### What to choose instead
If you’re looking for a rich, satisfying seafood dish, salmon is an obvious alternative.
You can also choose a milder white fish such as cod or haddock.
If a menu describes a fish as extremely buttery or oily and you aren’t familiar with the species, it’s reasonable to ask what you’re actually ordering.
## 9. Raw or Undercooked Fish of Uncertain Handling
This category isn’t about one species.
It’s about preparation.
Raw fish can be delicious.
Sushi, sashimi, ceviche, and rare seared fish are enjoyed around the world.
But raw or undercooked seafood carries different food-safety considerations from fully cooked fish.
Parasites and harmful microorganisms can be a concern.
Proper sourcing, freezing practices, refrigeration, handling, and preparation all matter.
That doesn’t mean every sushi restaurant is dangerous.
Reputable establishments have food-safety procedures specifically designed for raw seafood.
But if you’re eating somewhere that doesn’t appear to handle seafood carefully, it’s worth thinking twice.
### What to choose instead
Order fully cooked seafood if you’re uncertain about the restaurant’s handling practices.
Grilled salmon, baked cod, roasted trout, or thoroughly cooked shrimp can all be excellent choices.
Certain people should be especially cautious about raw or undercooked seafood, including pregnant individuals, young children, older adults, and people with weakened immune systems.
## 10. “Mystery Fish”
Perhaps the biggest warning sign on a restaurant menu isn’t a particular species.
It’s a lack of information.
A menu might advertise “fresh catch,” “white fish,” “reef fish,” or simply “local fish” without specifying exactly what you’re eating.
That can make it difficult to assess mercury exposure, sustainability, allergens, or even whether the menu description accurately reflects the species.
You don’t need to interrogate your server every time you order seafood.
But if the restaurant gives you little information, asking one simple question can help:
**“What species is the fish, and where was it sourced?”**
A good restaurant should generally be able to answer.
If nobody knows, choosing something more clearly identified may be the better option.
# The Restaurant Preparation May Matter More Than the Fish
There’s another important point.
A fish can be nutritionally excellent and still become a heavy meal depending on how it’s prepared.
Consider salmon.
Grilled salmon with vegetables is a very different meal from salmon battered, deep-fried, and covered in a rich cream sauce.
The same applies to cod.
Cod can be a lean protein.
But once it’s breaded, fried, and served with a large portion of fries and creamy sauce, the nutritional profile of the entire meal changes.
When ordering seafood, consider the preparation as well as the species.
Grilled, baked, broiled, steamed, or roasted preparations are often lighter choices than deep-fried options.
## Don’t Be Afraid of Fish
After reading a list like this, someone might conclude that ordering seafood at a restaurant is too complicated.
It isn’t.
Fish remains a nutritious food for many people.
The goal isn’t to avoid seafood.
The goal is to become a more informed seafood consumer.
Instead of asking, “Is fish healthy?” ask better questions.
What species is it?
Where was it caught or farmed?
Is it high in mercury?
How often do I eat it?
How was it prepared?
Is it sustainably sourced?
Those questions give you much more useful information.
# What Are Some Better Restaurant Choices?
If you want seafood that is generally considered a good option, several choices are worth considering.
## Salmon
Salmon is rich in omega-3 fatty acids and protein.
It can be grilled, baked, roasted, or served in salads.
Ask whether it is wild or farmed and where it comes from if sourcing matters to you.
## Trout
Trout can be an excellent alternative to higher-mercury predatory fish.
It is flavorful without necessarily requiring a heavy sauce.
Grilled or roasted trout with vegetables can make a balanced meal.
## Sardines
Sardines may not be the first fish people think of when dining out, but nutritionally they can be excellent.
They are small fish and can provide omega-3 fatty acids, protein, vitamin B12, and other nutrients.
## Cod
Cod has a mild flavor and firm, flaky texture.
It’s often an accessible choice for people who don’t enjoy strongly flavored seafood.
Just pay attention to preparation.
Baked cod is very different from heavily battered fried cod.
## Haddock
Haddock is another mild white fish that can work well grilled, baked, or broiled.
As always, sourcing matters, particularly when sustainability is important to you.
# Variety Is One of the Best Strategies
One of the simplest ways to reduce concerns about mercury is to avoid eating the same higher-mercury fish repeatedly.
Variety matters.
Instead of eating tuna several times every week, rotate different types of seafood.
One week you might have salmon.
Another meal might include trout.
Another might feature sardines.
Another could be cod.
This provides nutritional variety while reducing repeated exposure to any one potential contaminant.
# Ask Questions Without Feeling Awkward
Some people feel uncomfortable asking restaurant staff where seafood comes from.
Don’t.
It’s a reasonable question.
You can simply ask:
“Is this wild-caught or farmed?”
“What species of fish is this?”
“Where is it sourced from?”
“Is it high in mercury?”
“Can you prepare it grilled instead of fried?”
A restaurant that takes seafood seriously should understand why customers care.
## The Bottom Line
There isn’t a universal list of fish that nobody should ever eat.
Individual circumstances matter.
Mercury exposure matters.
Frequency matters.
Preparation matters.
Sourcing matters.
And sustainability matters.
Swordfish, shark, king mackerel, certain tilefish, bigeye tuna, and orange roughy are examples of fish that deserve particular attention because of mercury concerns.
Escolar has a different issue related to its natural composition.
Raw seafood raises food-safety considerations.
And vague “mystery fish” descriptions make it harder to know what you’re actually eating.
None of this means you need to stop ordering fish.
Quite the opposite.
It means you can become a smarter seafood customer.
Choose a variety of species.
Pay attention to preparation.
Ask where seafood comes from.
Be aware of mercury guidance, especially if you’re pregnant, breastfeeding, feeding young children, or otherwise in a higher-risk group.
And don’t assume that “healthy” automatically means “risk-free.”
The next time you open a restaurant menu and see a long list of seafood choices, don’t panic.
You don’t have to memorize every species.
Just pause for a moment.
Ask what you’re ordering.
Ask how it was prepared.
And if you’re unsure, choose a well-identified, lower-mercury option such as salmon, trout, sardines, cod, or another appropriately sourced fish.
The best seafood choice isn’t necessarily the fanciest item on the menu.
Sometimes it’s simply the one you understand well enough to order with confidence.
