An Analysis of Kaskeses: Past and Present

1.Identifying a Kaskeses

The Pasuk in Vayikra 11:9 describes a kosher fish as one that has “snapir v’kaskeses”, which is generally translated as fins and scales. From the Pasuk alone, one might think that a fish needs to have both simanim in order to be kosher. However, the Mishnah in Niddah 59A (expounded in Chullin 66B) tells us, “kol sheyesh bo kaskeses yesh bo snapir”, that any fish which has “kaskeses” will automatically possess “snapir”. Accordingly, in order to determine the kashrus of the fish, it would not be necessary to look at whether a fish has snapir. Instead, we simply need to confirm that it has “kaskeses”. The question remains, however, what exactly is “kaskeses”?

The Gemara discusses the definitions of “snapir“ and “kaskeses”, and concludes that “ snapir ” refers to a fin that assists a fish in swimming, and that “kaskeses” refers to those fingernail like protrusions on the side of a fish. The Gemara asks (in light of the knowledge that every fish possessing “kaskeses” automatically has “snapir” ) what the need was for the pasuk to mention “snapir”. The Gemara responds, “Yagdil Torah V’Yadir”, that the pasuk mentions “snapir” in order to “make great” and “aggrandize” the Torah.

Which scales are kaskeses?
So, what exactly is “kaskeses” ? Though it is often translated as “scales”, not all scales are included in the term “kaskeses”. The Ramban in Chumash tells us that a “kaskeses” must be able to be removed from the fish either by hand or with a knife, without ripping the underlying skin. Practically speaking, if the scale underneath the skin would rip upon removing the scale, the fish could have “fins and scales”, but not have “snapir v’kaskeses”, and it would not be kosher. The Ramban’s requirement is discussed in the Achronim , but is universally accepted as the halacha (see glosses of the Ramah on Y.D. 83 in the name of Maggid Mishnah).

The Poskim do not require that a kaskeses must have a particular shape, color or texture. Any scale that can be removed without ripping skin would qualify as a “kaskeses”. The only limit discussed is the size of a scale, namely that it must be large enough to be viewed by the naked eye. Both the Aruch HaShulchan and the Tiferes Yisroel mention that the kaskeses must be perceivable by the naked eye from a normal distance in order to be halachicly significant. A single “kaskeses” anywhere on the fish , appearing at any point during its lifetime is sufficient for it to be kosher. Even if the “kaskeses” fell off before the fish was caught or if the fish had yet to grow a “kaskeses” (but is of a species known to grow “kaskeses” later in life), the fish is still kosher.

Applying the definition of kaskeses to the various species of fish is not always simple. Some claim that one can look at the scientific classifications of scales in order to determine whether the scale qualifies as a kaskeses. Scientifically, there are five different types of scales: placoid, cosmoid, ganoid, ctenoid and cycloid. Placoid scales are found on many different types of sharks (sharks do have scales, though they rip the skin when removed and thus cannot be considered “kaskeses ” ), cosmoid are found on lungfish, ganoid are found on sturgeon, gars and bowfin. These three types of scales are rarely found on kosher fish, though I mentioned bowfin (Amia Calva) as at least one example of a kosher fish with ganoid scales. The other two types, cycloid and ctenoid scales, are the ones found on most kosher fish. The scale classifications are based on varying factors, such as the make up of the scale, its relationship to other scales on a fish, and the structure of the growth rings on the edge of a scale (experts can determine how old a fish is by counting rings on its scales, much as they would rings on a tree).

Some Rabbis have postulated that any fish bearing cycloid or ctenoid scales is a kosher fish. There are several reasons why one should disagree with this assertion. One reason is that some cycloid scales are not visible to the naked eye. For example a type of sand-eel (Ammodytes Americanus) is described as having cycloid scales. Rabbi Juravel, Rabbi Herbsman and I checked samples for scales, and none of us was able to see anything on the fish that was large enough to consider it as having “kaskeses”. Another reason why defining the type of scale is not sufficient to know if it is kosher, is that some fish have embedded scales. American Eel (Anguilla Anguilla) is known to have scales that could be “kosher” if not for the fact that they are deeply embedded into the skin. The same is true for burbot (Lota Lota). There is nothing intrinsic to the definition of any type of scale that requires it be able to be removed from the fish without ripping the skin, as is required for “kaskeses”. Therefore, looking at the scientific category of a scale is insufficient for purposes of identifying kosher fish.

Kosher fish lists
Can a kosher fish list be constructed for the benefit of consumers? While kashrus agencies have compiled lists, many agencies no longer do that. Lists, however, are not a viable solution. The same common name can be used to refer to a myriad of different fish, some kosher and some not. Not all “cods” are kosher; the non-kosher burbot mentioned above is classified as a “gadidae”, technically making it a cod. Other examples include “torsk”, which can refer to both a kosher and a non-kosher fish, “escolar”(oil-fish) which also refers to multiple specimens of varying kosher status, and turbot where some are kosher and some not.
The Kaf HaChaim also sees common names as inaccurate. In his Sefer (Yoreh Deah 83:5), he notes that discrepancies between different Talmudic accounts of the “shibbuta” must lead one to conclude that there were multiple fish called “shibuta” in the times of Chazal.
To summarize, fish that have a kaskeses are kosher. The definition of kaskeses is unique to kashrus, and scientific classifications of scales are not halachicly determinative. An article describing practical applications will be IY”H forthcoming.

2.Determining if a fish is kosher

Until now, we discussed what the requirements are for fish to be kosher (i.e. that the fish needs to have “kaskeses ” and what is a “kaskeses ” ), as well as some of the common mistakes made in trying to determine which fish would qualify as kosher. The question still remains, how does one know if a fish is kosher? We will now discuss two practical methods of determining if a fish is kosher.

Checking for kaskeses
The easiest way to determine if a fish is kosher is by manually checking the fish for a scale. Simply locate a scale on the side of the fish (preferably behind the gills, tail or fin – as mentioned in the above footnote #2 – as a chumra to guarantee the scale did not fall off of another fish), grab it between your thumb and forefinger, and gently attempt to pull it out. One should note that scales are always attached to the fish on the side closer to the head. The reason is fairly obvious if you can imagine how a fish swims. If the scale would be attached to the skin at the side closest to the tail, the current would pull the scale away from the skin and would inevitably rip it off as the fish swims. Imagine an open umbrella in a brisk wind that is not pointed in the direction of the blowing wind. The umbrella would get caught in the wind and blow inside out. So too, the current would get caught under an inverted scale and rip it off, causing the fish to be exposed to infection.

After removing the scale, simply inspect the area where the scale came from and check if there is a rip in the skin. If the skin seems fairly undamaged, the fish is kosher. If the scale will not come out without the skin ripping, the scale is not a “kaskeses”. Generally speaking, it is fairly obvious if the skin ripped. As a practical way to get a sense of what skin normally looks like when a “kaskeses” is removed (and the skin does not rip) one could inspect the scale-less skin of fish which one knows to be kosher.

As long as a fish has “kaskeses” at some point in it’s lifecycle it is permitted and there is no requirement of “mesorah” (i.e. a tradition that identifies a particular fish as a kosher species). Fish that lose their scales, often have a single scale in the three areas mentioned earlier in footnote #2 (behind the gills, tail and fin), though even without a scale present one could still recognize a kosher species of fish based on its skin. The Darchei Teshuva describes the possibility of determining the kosher status of a scale-less fish based on “mesorah”. The “mesorah method” is derived from an idea mentioned in our previous article, namely that the Gemara tells us that a fish that has not yet grown “kaskeses” or lost its “kaskeskes” is still a kosher specie. One should ask, even if theoretically true, how could one practically determine that the fish is kosher if there are no “kaskeses” on it now? The answer, says the Darchei Teshuva, is that one can recognize the specie based on its skin. There is no mention of someone with a “tvias ayin” on the flesh of a fish, which must be regarded as “kirvei dagim” and is forbidden.

Therefore, one may bring a fish whose “kaskeses” fell off or did not yet grow “kaskeses” – but whose skin is still attached – to someone familiar with the specific fish to determine if this is a species that is subject to a mesorah of being a kosher fish. This “mesorah method” of determining kosher status is particularly useful when dealing with various types of mackerel. Mackerels tend to lose their scales when removed from the water, and the mesorah method can be used to permit the scale-less mackerel. Generally, this mesorah method does not apply to fish whose skin is removed.

It is essential to note that the person ruling on the fish must be both “halachicly” reliable and familiar with the issue at hand (in our case, the specific type of fish). A typical worker at a fish store is not qualified to confirm the kosher status of the fish.

Some have asked how big a piece of skin must be left on the fish for one to determine its status based on the “mesorah method”. Though I have not seen a specific size given, clearly the piece of skin must be big enough for someone to actually be able to say what species it is. A few weeks ago, I received an inquiry from a small hashgacha organization, that wanted to know how they could accept as kosher fish whose skin had been completely removed except for a small (scale-less) patch, when their mashgiach could not properly identify the fish. I answered that they could not. The only way to accept the fish is if someone familiar with the specie accepts the delivery, and a mashgiach who is not familiar with the specific fish is not qualified to accept such fish.

Consider the following mashal (parable). Suppose a person, r”l, is blind. Halachicly, the person is “ne’eman” to testify in Beis Din. One would not, however, ask the person to confirm which of two identical pieces of meat has a hashgacha printed on the package. Here too, a person who does not have mesorah on the particular fish in question may not be relied upon to confirm the kosher status of the fish by a patch of skin. Such a person could only attempt to remove a scale from the fish, as described above.

Some hashgacha organizations allow for salmon to be accepted without skin at all. The justification behind this policy is that there are no known fish whose flesh resembles the red/pink of a salmon, making the flesh color a “siman muvhak” (an absolute identifier of the fish, which would pre-empt the requirement of checking for scales). Again, this heter would only apply to a case where the mashgiach accepting the fish knows what a salmon is supposed to look like.

Many of us are “zoche” to live in areas where we don’t much think about which fish are kosher or not, as we could not imagine the local “heimish” supermarket selling a non-kosher species. Some of us live in parts of the world where kosher meat is difficult to acquire, and buying fish from the local store is the easiest way to properly feed our families. Though it may seem odd at first, people living neighborhoods that do not have kosher fish stores have at least one advantage over their brethren living in neighborhoods that do. They have the chance to teach themselves and their children how to determine if a fish is kosher, often having no other option. It would be unfortunate if those of us who can easily acquire a kosher fish would lose out on the opportunity to know how to be “mavchin bein hatamei u’bein hatahor”, to be able to distinguish between the pure and the impure.

OU Kosher Staff