What is So Bad About Escolar?

Most of the mislabeled seafood you encounter is only harmful to your financial health. However, some sushi fish can cause problems with your digestive health. A ridiculous amount of fish served as “white tuna” which is supposed to be albacore is actually escolar, one of the most notorious fish sold to the public. How bad is it? They don’t call it “Ex-Lax of the sea” for nothing.

Escolar is a type of oilfish/snake mackerel with white to pink, oily meat. Within the past few decades escolar has gone from albacore by-catch to a commercial species in its own right. From my own upbringing I know the value of underutilized species; there are lots of plentiful, good tasting species that most consumers never see.

Escolar is Not White Tuna – Here is Why


To its credit, escolar is actually a very good tasting fish, and you can find recipes and other information about how to cook it. but the oil we are talking about is not the good oil we look for in fish like salmon. Escolar oil is not really oil at all, but a waxy ester that is indigestible and can lead to stomach cramps and oily diarrhea within a half hour of consumption. California Sea Grant states that up to 20% of the total body weight is made up of this indigestible substance.

Escolar or oilfish (i.e. Lepidocybium flavobrunneum or Ruvettus pretiosus) contains a strong purgative oil (wax ester), called gempylotoxin, that may cause diarrhea, abdominal cramps, nausea, headache, and vomiting when consumed.

FDA advises against importation and interstate marketing of these fish.

If this was a rare occurrence in restaurants, there would be no cause for alarm. However a multi-year study by Oceana Canada (who I’ll side with on this front) found 84% of their white tuna samples were actually escolar. No wonder Italy and Japan have banned its importation.

To go along with flat out fraud and mislabeling, some restaurateurs have admitted they thought white tuna was a marketing term for escolar. I’ve even heard this myself from a guy that makes sushi for a supermarket. It is also mistakenly labeled as “butterfish” or as a “sushi-grade species called Hawaiian Walu.

When I originally posted this article there was a fish market online that went to great lengths to praise walu’s silky taste and texture, but nowhere do they say it is really escolar. This was on top of a blog post where the same company refuted Oceana’s claim of mislabeled fish. I’m glad to see they have removed all of this from their website and so I removed the links. The truth is, the only name escolar can be sold under in the US is escolar, don’t let any so-called expert tell you differently. If they are not upfront about this, then it is fraud.

For someone with gastrointestinal issues, this fish can turn a fun night out into a nightmare. I am one of those people, and have even adjusted many of my recipes for that reason. If I ever consumed more than a small amount of mislabeled “white tuna” I would probably have to go to the emergency room.

I have to admit, I would not be able to tell at first glance if my nigiri is really albacore or escolar. The taste is similar enough as well, which is a scary thought considering what this fish can do to you. Make sure you get sushi from reputable sources, talk up the sushi chef and make sure they know what they are actually serving. And if all else fails, keep your dubious butterfish, walu, or “white tuna” consumption to portions under six ounces.