Butterfish has won over the palates of Japanese food enthusiasts and has become fashionable in numerous restaurants, especially those offering sushi and other Asian cuisine. However, many doubts, confusions, and debates still surround it, particularly regarding its true identity, the safety of consuming it, and the different species that are mistakenly referred to by this name.
Read on to discover all the details about butterfish : characteristics, related species, habitat, its presence in international cuisine, precautions when consuming it, and the keys to distinguishing it from other varieties.
Biological characteristics and morphology of the butterfish
The fish traditionally known as butterfish exists and can refer, depending on the region, to different species.
The original butterfish , also known as the blue butterfish (family Stromateidae) , is a medium-sized fish, typically between 15 and 20 cm in length. It has an elongated, somewhat flattened body , vaguely resembling that of an eel. Its dorsal fin is long, extending from almost behind the head, and has soft, spiny rays . The anal fin reaches halfway down the body, and the caudal fin is more rounded. The distinction between the dorsal and anal fins is very clear, and the pelvic fins are tiny.
Its head is small and its mouth is upturned, with the lower jaw being particularly prominent. Its eyes are easily identifiable because they have a distinctive dark vertical line just below them. The body is brown with regular yellowish spots , and along the base of the dorsal fin, there are between 9 and 13 dark spots, each bordered by a light yellow ring. These spots appear as the fish ages and grows.
This animal also has a slimy, slippery skin in which the scales are hidden. This entire profile, along with its white tones and firm texture, leads to its being compared to butter on the table.
Feeding and reproductive cycle
In their natural environment, butterfish feed primarily on small benthic organisms, eggs, and various marine invertebrates . Some species also supplement their diet with small fish, crustaceans (such as sand fleas), and worms, adapting to the food available on the seabed and in rocky areas. For more information on other related varieties, you can consult our dedicated section on blobfish.
Less data exists regarding the reproduction of the butterfish, as many details remain unclear , especially in regions like the Baltic Sea or the American coasts. It is known that the female spawns in winter, laying her eggs at the base of shells or under stones, in nests prepared by the male. The male remains with the eggs, protecting and oxygenating them by moving his tail, until they hatch.
Geographic distribution and habitat
Butterfish can be found primarily in coastal and deep waters . They have been recorded off the coasts of Chile, Argentina, and the Falkland Islands, as well as in areas of the Baltic Sea, from Sipoo (east of Helsinki) to Kaskinen in the Gulf of Bothnia, and even in some locations near the Åland Islands. Similar species also exist in the Atlantic and Pacific Oceans. To explore other similar species, you can visit the section on ocean sunfish.
It preferentially inhabits rocky and vegetated seabeds at varying depths—usually from 10 meters up to 50 meters in some regions. It behaves like a fish that hides under rocks and leaves during the day and comes out at night in search of food.
Confusion and gibberish: How many fish are called butterfish?
There is enormous confusion in the market regarding which species butterfish actually is. In Spain and other European countries, three or four different species are labeled as "butterfish," depending on the region and the restaurant. This mix of names leads to misunderstandings on restaurant menus, at the point of purchase, and for the end consumer.
The main species known as "butterfish" are:
- Palometa (Stromateidae) – It is the original, authentic butterfish, with a rounded, flat body, a short ventral fin, and long pectoral fins. It is not usually used for sushi, but is mostly consumed grilled or marinated with miso in recipes such as Managatsuo o Misoyaki butterfishIt is very common in more traditional Japanese cuisine.
- School (Lepidocybium flavobrunneum y Ruvettus pretiosus) – Erroneously called butterfish, it has an elongated body, resembles a barracuda, and is used primarily in sushi and sashimi in Japanese restaurants outside of Japan. It is known for its white, fatty meat, but it can cause digestive problems due to its high wax ester content. It is banned in Japan and Italy due to these risks.
- Black cod (Anoplopoma fimbria) – Also known as black cod, gindara, or sablefish. Although it's called "cod," it's not a traditional cod. Its texture is soft, its flavor delicate, and it's highly valued in Japanese cuisine, especially for marinated and baked recipes, but it's not usually eaten raw.
- Sometimes, it is added black pomfret to the list of "butterfish", although its use is less common and depends on the region.
The mixing of names encourages confusion, and therefore, it is essential to always request information at the point of sale or consumption to know what species we are actually eating.
Nutritional properties and composition of butterfish
Butterfish is prized for its firm, juicy, white flesh with a fatty texture . This combination gives it a very delicate mouthfeel, and it literally "melts" with every bite. Its velvety texture and high content of healthy fats (primarily omega-3 and omega-6 fatty acids in native species) make it a premium ingredient for haute cuisine.
Some species, such as escolar, contain up to 18 to 21% total fat , mostly composed of wax esters . These fats cannot be digested by the human digestive system, which is why they can cause episodes of oily diarrhea or keriorrhea , especially if consumed in large quantities. This characteristic has led to their consumption being regulated and, in some places, restricted or prohibited.
In contrast, both pomfret and black cod provide high-quality protein , low calorie content (if consumed in moderate portions), vitamins and minerals – especially Omega-3, vitamin D and selenium – and are an excellent choice for balanced diets.
Butterfish in Japanese and world cuisine
In haute Japanese cuisine, butterfish is considered a delicacy, primarily for its color, texture, and flavor. It is commonly used in the preparation of sushi, nigiri, sashimi, and in dishes such as tataki or miso-glazed black cod. However, the species most often used for sushi outside of Japan is not the original pomfret, but rather escolar , a more economical option with an equally delicate flavor.
In Spanish cuisine, butterfish appears on the menus of sushi places and Asian restaurants, although it's important to read carefully to identify the exact type of fish used and whether its consumption may be inadvisable for people with digestive sensitivities.
Sushi, nigiri and other traditional recipes with butterfish
The most popular butterfish recipe outside of Asia is nigiri : a rectangular slice of raw butterfish on a ball of vinegared rice. Escolar is the most commonly used fish for this preparation, and its oily, delicate flavor pairs well with light soy sauces and wasabi.
Other internationally recognized elaborations include:
- Butterfish sashimi – Thinly sliced loins accompanied by soy sauce, wasabi, or pickled ginger.
- tataki – Butterfish briefly pan-fried, leaving the flesh raw inside. Marinate with olive oil and sesame sauce and cut into very thin slices.
- Miso-glazed black cod – Gindara, marinated for several hours in sweet miso and baked over high heat. A signature dish of contemporary Japanese cuisine.
- Stir-fries and soups – Preparations with Asian vegetables, oyster sauce, cured fish, or fresh presentations for salads, tartar, or ceviche.
In traditional Japanese cuisine, pompano ( Managatsuo ) is typically grilled and marinated in miso for several hours, which enhances its flavor and preserves the tender texture of its flesh. In America and some Western restaurants, escolar is preferred, which lends itself well to gratins, quick pan-fries, and light side dishes. In all cases, the most common presentation is as fresh fillets , breaded, grilled, or raw, although there are also dehydrated or cured options for appetizers and salads.
Risks, controversies and consumption recommendations
Despite its benefits, consuming butterfish—especially escolar— can cause side effects in sensitive individuals . The main risk lies in the wax esters naturally present in escolar and black escolar. These fats are not digested and can cause discomfort such as oily diarrhea (keriorrhea), nausea, headache, and abdominal cramps . The effects can appear anywhere from a few hours to 90 hours after ingestion, and their severity varies depending on the individual's tolerance and the amount consumed.
For this reason:
- It is recommended to limit the amount consumed per person to no more than 100-170 grams (depending on local legislation and the species).
- Avoid raw consumption by sensitive individuals, children, and pregnant women.
- Only consume escolar or black escolar if indicated on the label or in the restaurant warns of possible gastrointestinal effectsIn Spain, regulations require consumers to be informed of these risks.
- Promote cooked preparations (grilled, baked, or stewed) that facilitate the digestion of some of their fats.
- Remove skin and excess visible fat before cooking.
In Japan and Italy, escolar and black escolar are prohibited for human consumption. In Spain, they can only be sold packaged and labeled with a risk warning.
There is no evidence of significant toxicity from the consumption of pomfret or black cod, provided that proper preparation guidelines are followed and current regulations are adhered to.
Key aspects for choosing and differentiating quality butterfish
To enjoy a good butterfish at home or in a restaurant, it's a good idea to follow some selection tips:
- Pay attention to freshness: : soft, marine scent, elastic and firm flesh to the touch, bright white color without spots.
- Check the origin and species: make sure that the purchase is of pomfret, escolar, black cod or other authorized species (avoiding fraud).
- Whenever possible, opt for products from sustainable fishing and certificates.
- Read the labeling carefully to identify the species and any possible warnings regarding consumption.
Featured recipes and preparation methods to get the most out of the flavor
Butterfish is a versatile ingredient in the kitchen. Several recipes and techniques stand out that respect and enhance its original texture:
- Laminated with black truffle: Thin fillet of butterfish marinated in lemon and tiger's milk for 30 minutes, accompanied by lumpfish roe, toasted corn, Maldon salt, pomegranate seeds and fresh parsley for garnish.
- Toasted nigiri with truffle sauce: A cut of butterfish lightly seared and accompanied by truffle sauce for a contrast of exceptional flavors.
- Miso-glazed black codMarinated in miso, sugar, and sake, then baked until caramelized. Recommended for black cod, not escolar.
- tataki: A piece briefly pan-fried with olive oil and sesame, chilled on ice, and sliced thinly. Perfect for serving with turnip strips and rice.
- Stir fry: Butterfish accompanied by Asian vegetables and oyster sauce, preserving the sweetness and enhancing the oriental flavors.
It's also important to note that the skin of escolar should never be eaten due to its high concentration of wax. For those who prefer mild flavors, butterfish is ideal both raw (if the species is selected appropriately) and cooked. Ultimately, learning how to select and prepare butterfish correctly allows us to enjoy its qualities safely and deliciously.
Butterfish remains a popular ingredient in international cuisine, especially in modern Asian haute cuisine, thanks to its unique texture, flavor, and quality . With the right information about the species, associated risks, and preparation options, any food lover can enjoy this fish with complete confidence and maximum culinary pleasure.