Photo Credit: Rabbi Slifkin

The swordfish is one of the most extraordinary creatures in the sea. One of the largest, fastest, and most aggressive of all bony fishes, it starts its life the size of a grain of rice and can grow to over 1,000 pounds.

The function of its sword – which is a third the length of its body and sometimes impales boats – is unknown. Found around the world and traditionally often caught by means of a harpoon like a whale, the swordfish has been the fish of legends for millennia. But is it kosher?


In Orthodox circles today, it is widely believed that the swordfish is unequivocally non-kosher. Yet, this belief is simply wrong. In 1933, a list of kosher fish published by none other than Agudas HaRabbonim – the premier right-wing Orthodox rabbinic organization of the early 20th century, under the leadership of Rav Eliezer Silver – included swordfish!

And the following year, with the organization under the leadership of Rav Yosef Kanowitz, the list was reprinted with swordfish on it – even though other fish had been removed after criticism from detractors.

Rabbi Dr. Ari Z. Zivotofsky, in “The Turning of the Tide; The Kashrut Tale of the Swordfish” (BDD 19, January 2008), has thoroughly documented how traditionally, the swordfish was considered kosher, and how this assumption changed in the latter half of the 20th century. While the rejection of the historical tradition is understandable, there are strong grounds for justifying it.


The Sages and the Swordfish

The Talmud (Chullin 66b) and Tosefta (Chullin 3:27) mention a fish called achsaftias as being kosher. The word achsaftias is not Hebrew or Aramaic; it is an Aramaicized version of a Greek word. This appears to be the Greek word xiphias, which refers to the swordfish (based on the Greek xiphos, which refers to a sword). From the outset, then, there is reason to believe the swordfish is the achsaftias of the Talmud and is kosher.

The swordfish, Xiphius gladius, is one of a group of large predatory fishes with swordlike projections known as billfish. Other billfish are several species of marlin, sailfish, and spearfish (which have relatively short bills). But whereas the bills of other billfish are round in cross-section – like spears – that of swordfish are flat in cross-section, like swords. Accordingly, any reference to a fish named “sword” presumably refers to the swordfish.

Furthermore swordfish are by far the most common of all billfish species in the Mediterranean. If swordfish weren’t kosher, the Talmud would not describe another billfish as kosher and mislead people into thinking it was talking about the more common swordfish.

Interestingly, the Talmud presents the achsaftias as an example of a fish that is kosher even though it does not have scales. It says this fish is born with scales but sheds them when it is taken out of the water. Now, swordfish are not known to do this. However, no other fish is known to do this either.

As we shall see, there is another explanation for the Talmud’s statement. But there is every reason to believe the swordfish, and none other, is the fish being discussed in the Talmud.


The Knesses HaGedolah and the Universal Tradition

The next significant discussion about swordfish is found in the writings of the renowned 17th century halachic authority from Turkey, Rabbi Chaim ben Yisrael Benvenisti, known as the Knesses HaGedolah. He writes as follows: “It is a widespread custom among all Jews to eat the fish with the sword, known in vernacular as fishei espada, even though it does not have any scales, because it is said that when it comes out of the water, due to its anger, it shakes and throws off its scales.”

This statement is cited as authoritative, without dispute, by a number of prominent authorities, including the Pri Megadim, Darchei Teshuva, Chida, and Kaf HaChaim. There is also clear testimony that swordfish was eaten in many communities under rabbinic approval, as noted earlier. In fact, it seems that before the 1950s, nobody at all questioned its kosher status.

In 1951, though, Rabbi Dr. Moshe Tendler examined a swordfish and did not find any scales. He became convinced it was not a kosher fish and, furthermore, that it could not be the fish described by the Knesses HaGedolah. Rabbi Tendler therefore launched a campaign against the consumption of swordfish.

Rabbi Isser Yehudah Unterman countered with a heated response, but Rabbi Eliezer Waldenberg took the side of Rabbi Tendler, and a fierce debate erupted in halachic journals in the 1960s. (Unfortunately, though, all sides suffered from a lack of accurate information on swordfish and other billfish.)

Meanwhile, the Conservative movement ruled that swordfish are kosher. Rabbi Tendler subsequently published an article in The Jewish Observer describing the situation as a dispute between Orthodoxy and Conservative Jews – and thus naturally the rest of the Orthodox community decided to take his side.

However, it is abundantly clear that the Knesses HaGedolah was indeed referring to swordfish. The name he uses for it, fishei espada, is the name for swordfish in numerous Mediterranean countries.

Rabbi Tendler argues that he was referring to sailfish – but these are rarely found in the Mediterranean, and the Knesses HaGedolah speaks about a commonly-found fish. Since people in that region were widely eating swordfish – the most common billfish – it is inconceivable that the Knesses HaGedolah would use “fishei espada” to refer to a different fish and not mention any problem with the swordfish.


Shedding Light, Not Scales

We have seen that there is a widely supported ruling from the Knesses HaGedolah that swordfish are kosher (which seems to go back as far as the Talmud), together with longstanding testimony that it was commonly eaten. In light of these facts, we should try to validate this ruling and practice as there is a halachic principle that we avoid casting aspersions on earlier generations.

If there were no solid grounds for us to independently permit swordfish, we would find ourselves in a difficult position and would have to refrain from eating it. But in this case, the longstanding halachic position and general practice can indeed be independently justified:

Juvenile swordfish, until around four feet in length, are seen to possess scales, in two varieties – smaller ones with a single spine emerging from them and larger ones with several spines.

Contrary to ancient belief, the apparent absence of these scales in adults is not because they are shed when the fish is removed from the water; as noted, no fish that does that. Rather, it is because by the time the swordfish reaches adulthood, its skin has thickened around the scales such that they are barely, if at all, detectable.

(Note that the swordfish is the only billfish in which this happens. With all other billfish, the situation is exactly the opposite of that described by the Talmud and Knesses HaGedolah – they lack scales as juveniles but develop them as they mature. This fact is further evidence that other billfish could not be the fish described by the Talmud and Knesses HaGedolah.)

If a fish has scales as a juvenile, but lacks them as an adult, is it kosher? The Talmud only discusses the kashrus of fish that gain scales as adults and lose them as a result of being removed from the ocean, not the kashrus of fish whose scales naturally change into an unacceptable variety.

However, the Aruch HaShulchan (Yoreh De’ah 83:16) states that the Talmud’s dual permissions to eat fish that later grow scales and fish that lose scales when removed from the sea serve to signify that scales need only be a feature of the species, not of any individual fish at any given time.

Furthermore, there is a simple logical reason why a fish that starts life with appropriate scales must always be deemed kosher. Jewish law allows one to eat a fish based on the presence of fins and scales even if one does not know the species. But if the subsequent loss of scales would mean the fish is not kosher, how could one ever rely on the current presence of scales to be sure the fish is kosher?

It must be the case, therefore, that just as a fish that later grows scales is kosher, so too a fish that has scales early in life is kosher.


The Scales of the Swordfish

Do the scales of swordfish qualify as kosher scales? The Ramban states that scales must be detachable, which, notwithstanding the apparent lack of basis for this rule in the Torah or Talmud, has been universally accepted as a halachic requirement. Do the scales of swordfish satisfy this requirement?

Swordfish scales are attached to the lower layer of the dermis along their entire base. They are thus more comprehensively attached than the scales of other fish such as carp. However, there are other kosher fish, such as perch, sea bass, sheepshead, and grouper, which likewise have scales that are relatively strongly attached. (Note that no less an authority than the Noda B’Yehuda rated even the scales of sturgeon as acceptable.)

Rabbi Tzvi Hirsch Shapira (Darchei Teshuvah 83:10-11 and especially 83:13) stresses that scales are valid even if they are attached all the way around their base, even if they can only be detached with a utensil and with effort, and even if there is skin above them – as long as there is also skin beneath them. With swordfish, the entirety of the stratum compactum (the lower layer of the dermis) lies beneath the scales.

A contemporary practical examination of the swordfish has been conducted by Rav Shlomo Machpud of Bnei Brak, one of the most respected authorities on kashrus today, in the presence of several other kashrus experts. He wrote that he performed a careful examination and found numerous scales that were easily detachable.

Rav Hershel Shechter has likewise stated in several forums that the swordfish is kosher, and attested that Rav Soloveitchik believed so as well (although others dispute this claim).


Eating Swordfish Today

To summarize: The Talmud refers to a fish called achsaphtias which is kosher even without scales due to its having formerly possessed them; there is every reason to believe that it is referring to the swordfish. There is even more reason to believe the Knesses HaGedolah is referring to the swordfish as he describes it using the common name for swordfish and notes that it is widely consumed; there is no other fish he could be referring to.

Finally, the swordfish indeed possesses scales, which disappear from view as it matures. While the halachic validity of these scales might be questioned, several contemporary halachic authorities have ruled that they found acceptable scales on it and that the swordfish is kosher.

Consuming swordfish today, however, is challenging for observant Jews since only adult swordfish are caught in the fishing industry, and they are enormous. Due to the impracticality of transporting and selling a 1,000-pound fish to the retail market, fishmongers instead buy loins and steaks.

Now, whereas the steak of a fish such as tuna can be purchased by the kosher consumer, since the scales are visible, there are no scales on an adult swordfish. So while the swordfish is kosher, the problem is: How one can be sure that the chunk of fish at a market is really from a swordfish? In fact, shark is sometimes marketed as swordfish!

In theory, it is possible to identify swordfish by the unique pattern of whorls in the flesh, but there doesn’t appear to be a rabbinic authority who is willing to rely on this. Thus, the only way to eat swordfish is to obtain the entire fish so that one can be sure it really is swordfish. Since a whole swordfish is rather difficult to transport and can cost well over a $1,000, a kosher consumer cannot easily obtain it.

Accordingly, when we decided to present swordfish at the “Feast of Legends from the Sea” – due to be held at the Biblical Museum of Natural History after Sukkos – we had a challenge on our hands. To make matters even more difficult, swordfish have been overfished in the Mediterranean and are now much less commonly found.

It took months of calling various fishermen until we finally struck gold with a fisherman based out of Ashdod who had caught a swordfish around six feet long. The price: 3,000 shekels! But our troubles weren’t over. We had to find a walk-in freezer big enough to store it!

All the effort will be worth it, though, when we finally eat it at what will be a very special halachic, and historic, feast.

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Rabbi Dr. Natan Slifkin is the director of the Biblical Museum of Natural History in Beit Shemesh and writes at