If you've ever heard of Walu fish before, you'll know it's quite a controversial sea creature to eat. With the untrained eye, Walu fish sliced and prepared looks like a delicious and tasty sashimi. Many fishmongers and seafood purveyors will sell it as a delicacy and a delicious treat. However, be warned. The tasty Walu Fish, also known as Escolar, comes with a price you may not want to pay. That's why we put together everything you need to know about eating the Walu fish.
With some varieties of fish in danger of being overfished and other species becoming undesirable due to their high mercury content, seafood purveyors need a fish that's delicious, cheap, sustainable, and low in mercury. And escolar fits the bill. It's economical and politically correct; it's also extremely tasty.
But before you eat it, there is something important you need to know.
So, What Exactly Is Walu Fish?
Escolar is a type of snake mackerel. Sometimes it's under the name "butterfish," "oilfish," or "waloo/walu." Sushi restaurants occasionally serve it as "super white tuna" or "king tuna." As mentioned above, it is, in many ways, the perfect fish: It's cheap, it's sustainable, and it's buttery and succulent.
So, what is wrong with eating Walu Fish?
Walu Can Be Dangerous to Eat
Escolar cannot metabolize the wax esters naturally found in its diet. These esters are called gempylotoxin, and this is what gives the flesh of escolar its oily texture. The downside is that these esters are are very similar to castor or mineral oil, and when full portions of escolar are consumed, they can cause gastrointestinal symptoms.
To be frankly and bluntly specific — and I'm sorry for this — consumption of escolar causes explosive, oily, orange diarrhea. People have reported that the discharges are often difficult to control and accidents can happen while passing gas.
I personally know someone who ate an escolar steak one night, unaware of its side effects. The next day he was riding the elevator to his office when out of nowhere his bowels unleashed a surprise attack on his pants. As he said later, "Thank God I had my gym bag with me, which had a clean pair of underwear in it." This explains why escolar is also called the "olestra fish" and the "ex-lax fish."
The Japanese and Italian governments have banned the importation and sale of escolar for these reasons. The governments of Canada, Sweden, and Denmark require that all escolar come with warning labels. The FDA lifted the escolar ban in 1992 because the fish is nontoxic (sure, it causes embarrassing things to happen in your pants, but it won't hurt or kill you).
Can You Eat Walu Fish?
In spite of all this, escolar is indeed very buttery and delicious, and should be enjoyed, but never in portions larger than six ounces. Portions below six ounces will not cause gastrointestinal distress. Don't say we didn't warn you.
Eating Walu Sushi/Sashimi
Has anyone ever told you that eating a certain type of food will make you sick? Mostly what they mean is that down the road, that pizza you just ate may cause you some kind of health problem. But there are foods that can make you sick shortly after eating them. I am not even talking about food that has gone bad, but something that people often eat fresh.
Escolar, also known as Oilfish, is a type of fish that many consider to be quite tasty, but in truth it is not good for you. Being a popular fish in some circles it is common to find escolar in restaurants, especially sushi bars. Even with it being openly served you should always take caution while eating this fish.
The main issue with escolar is that it has a lot of oils within its flesh. Unfortunately we have been trained to believe that all fish oils are good for you, but not all fish oils are Omega-3 oils. Escolar is full of what is called wax-esters. These are a type of oil that are inedible and the human stomach will not absorb it, but instead attempt to flush the system.
The result is the consumer of the fish may experience a mild to severe case of steatorrhea. In layman’s terms, you could have a very bad case of diarrhea. This onset could be so rapid that you could have symptoms within an hour of eating escolar fillet. The way the wax-esters get flushed through the body could result in anal leakage and accidental soiling of one self.
The steatorrhea can last from 2-36 hours, depending on how much you ate and on each individual case. Most people will chock up a case of this to basic food poisoning, but if you have these symptoms every time you eat sushi, then you may know the answer to why it is happening to you.
Walu vs. Tuna
It is not as simple to avoid escolar by just not ordering it. Escolar is one of the most common subjects of food labeling fraud in the US and in the world. The main reason is that escolar is relatively cheap and some consumers cannot tell the difference between tuna and escolar. It is such an issue, that escolar has been known to imitate or fraudulently replace dozens of fish.
The following fish are only an example of what escolar can be disguised as or called by: Albacore Tuna, Waloo, Chilean Sea Bass, Grouper, King Tuna (aka blue fin tuna), Black Cod, Butterfish, Blue Cod, Rudderfish, Pacific Cod and Atlantic Cod. It is usually a less than reputable or a cheap establishment that may pull the wool over your eyes and feed you this fish instead of the real fish that you requested.
But it is a common issue, as in 2009 5/9 New York restaurants who served Albacore Tuna were actually replacing it with escolar. Sometimes the chefs themselves may not know that they are being given bad product, but most of the time it is the business trying to make an extra dollar over this bait and switch tactic.
So if you have the runs after every time you eat at your favorite sushi spot, then you should consider the idea that you may not be eating what you actually ordered.
For the most part the only major issue with labeling fraud is that you may unexpectedly have to use the bathroom, but there are other issues that can be more serious. With labeling scams, a consumer may accidentally consume a type of fish that they are allergic to.
Most people who that will happen to may break out in a rash, but some people may have a more serious reaction that can lead to anaphylaxis and possibly even death. Even with this risk, the FDA refuses to look into cases of mislabeled food, stating that they do not have the resources to enforce any regulations on labels.
Walu Fish Meat: How to Prevent from Problems
First of all try and avoid places that you suspect of such practices. If you have symptoms of steatorrhea then take note on where you ate, and if the symptoms arise again after eating there, then avoid the restaurant.
There are also certain guidelines that you can follow to avoid getting sick from escolar. You should limit your consumption to 6oz per portion, and try to only eat the meat closest to the tail.
The method of cooking or storage of escolar fillet has no effect on the wax-esters in the meat. But, be warned that even with the precautions, you are still at risk of having an accident because you ate escolar.