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Science & Nature
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Escolar: The Delicious 'White Tuna' With an Oily, Unforgettable Secret
Escolar, a fish often mislabeled as 'white tuna,' is known for its buttery taste. However, its high content of indigestible wax esters can cause keriorrhea—a sudden, oily, orange anal discharge. While not dangerous, the effects are notoriously unpleasant and embarrassing for the unaware.
Imagine discovering a new favorite fish. It’s rich, incredibly buttery, and melts in your mouth, especially as sushi. You've seen it on menus labeled as 'white tuna,' 'super white tuna,' or 'butterfish.' You enjoy a generous portion, impressed by its decadent flavor. But hours later, you experience a bizarre, alarming, and deeply embarrassing digestive event. You've just met the Escolar, the fish with a delicious taste and a very oily secret.
What is this Treacherous Fish?
Escolar (Lepidocybium flavobrunneum) is a species of snake mackerel that lives in deep, tropical and temperate waters around the world. Its flesh is prized for its rich flavor and firm texture, making it a popular, albeit risky, choice in some culinary circles. The problem isn't that the fish is toxic or spoiled; the issue is woven directly into its biology. Escolar’s diet consists of other fish and squid that are high in wax esters, a type of fat that the Escolar cannot metabolize. Instead of processing them, it stores these waxy oils in its flesh, which can make up 14-25% of its body weight.
The Science of an Oily Catastrophe
Humans, like the Escolar, cannot digest these wax esters, which are scientifically known as gempylotoxin. When we consume more than a small amount of the fish, these oils pass through our digestive system untouched. Once they reach the colon, they accumulate and eventually have only one way out. This leads to a unique and unpleasant condition called keriorrhea, which literally translates from Greek to 'flow of wax.'
It's not your typical food poisoning. There are no cramps, no fever, no real warning. Just a sudden, uncontrollable, oily orange leakage that can ruin your clothes, your furniture, and your dignity. Many who have experienced it describe it as the ultimate food betrayal.
Symptoms and How to Avoid Them
Keriorrhea is distinct from standard diarrhea. The main symptom is an oily, orange or yellow anal discharge that can happen suddenly and without warning, sometimes up to 36 hours after consumption. It is not considered life-threatening or a sign of disease, but it is intensely unpleasant and socially disastrous.
Due to these effects, some countries like Japan and Italy have banned the importation and sale of Escolar. In the United States, the FDA has issued advisories but has not banned the fish. It is often found in sushi restaurants, frequently mislabeled as something more benign. So, how can you protect yourself?
- Ask Questions: If you see 'white tuna' or 'super white tuna' on a menu, ask your server if it is Escolar or oilfish. A reputable restaurant should be transparent.
- Portion Control is Key: If you decide to try it, consume a very small portion, generally recommended to be under 6 ounces (170g).
- Cooking Method: Grilling the fish on a rack may allow some of the oil to drain away, but this only marginally reduces the risk. The most important factor is how much you eat.
Escolar remains a paradox of the culinary world: a delicacy that comes with a potent, non-negotiable warning. While its flavor is celebrated by some, its after-effects serve as a powerful cautionary tale for any adventurous eater. It's a gamble where the stakes are your dry cleaning bill and your composure.