Askmoses-A Jews Resource
Am I allowed to take revenge against someone who has wronged me?
Browse our archives

The Scholar is ready to answer your question. Click the button below to chat now.

Scholar Online:

Type in your question here:

Click the button below to either CHAT LIVE with an AskMoses Scholar now - or - leave a message if no Scholar is currently online.


What is the Halachic definition of fins and scales?

by Rabbi Chaim Goldberg


Library » Mitzvot » Kosher » Kosher Creatures | Subscribe | What is RSS?


Consumers are becoming more health conscious.  Fish is often considered a healthier option compared to meat.  We are all familiar with certain fish like salmon and tuna.  Yet, some may want to broaden their culinary experiences and try some more exotic varieties of fish.  The question then becomes, what fish are Kosher?

This article will illustrate that it may not always be so simple to answer this question.

Identifying a Kaskeset

The verse1 describes a kosher fish as one that has “snapir v’kaskeset”, which is generally translated as fins and scales.  From the verse alone, one might think that a fish needs to have both signs in order to be kosher.  However, the Mishnah2  tells us, “kol sheyesh bo kaskeset yesh bo snapir”, that any fish which has “kaskeset” will automatically possess “snapir”.

Accordingly, in order to determine the Kashrut 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 “kaskeset”.  The question remains, however, what exactly is “kaskeset”?

The Talmud discusses the definitions of “snapir” and “kaskeset”, and concludes that “snapir” refers to a fin that assists a fish in swimming, and that “kaskeset” refers to those fingernail like protrusions on the side of a fish.  The Talmud asks (in light of the knowledge that every fish possessing “kaskeset” automatically has “snapir”) what the need was for the pasuk to mention “snapir”?

Some want to broaden their culinary experiences and try some more exotic varieties of fish. The question then becomes, what fish are kosher?
The Talmud responds, “Yagdil Torah V’Yadir”, that the verse mentions “snapir” in order to “make great” and “aggrandize” the Torah.

Which scales are kaskeset?

So, what exactly is “kaskeset”?  Though it is often translated as “scales”, not all scales are included in the term “kaskeset”.  The Biblical commentator Nachmanides tells us that a “kaskeset” 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 skin underneath the scale would rip upon removing the scale, the fish could have “fins and scales”, but not have “snapir v’kaskeset”, and it would not be kosher.  Nachmanides' requirement is discussed by the more recent Halachic authorities,3  but is universally accepted as the Halachah4

There is no requirement that a kaskeset must have a particular shape, color or texture.  Any scale that can be removed without ripping skin would qualify as a “kaskeset”.  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 Tiferet Yisroel mention that the kaskeset must be perceivable by the naked eye from a normal distance in order to be halachicly significant.  A single “kaskeset” anywhere on the fish,5 appearing at any point during its lifetime is sufficient for it to be kosher.  Even if the “kaskeset” fell off before the fish was caught or if the fish had yet to grow a “kaskeset” (but is of a species known to grow “kaskeset” later in life), the fish is still kosher.

Applying the definition of kaskeset 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 kaskeset.  Scientifically, there are five different types of scales: placoid, cosmoid, gadoid, ctenoid and cycloid.


  • 1. Leviticus 11:9.
  • 2. Niddah 59a (expounded in Chulin 66b).
  • 3. See Shu”t Nodeh B’Yehuda Tinyana 26-29 where he discusses the possibility of soaking a fish in “mai afar” in order for the scales to be removed without ripping skin. See Pitchei Teshuvah S”K 1 who explains why this opinion is not accepted l’halachah.
  • 4. See glosses of the Ramah on Y.D. 83 in the name of Maggid Mishnah.
  • 5. See Y.D. 83:1 and Ramah there who recommends one be stringent and require at least one “kaskeset” appear in one of three specific places on the fish – by the gills, tail or fin – based on a Tosefta.


Please email me when new comments are posted (you must be  logged in).
Torah is G–d’s teaching to man. In general terms, we refer to the Five Books of Moses as “The Torah.” But in truth, all Jewish beliefs and laws are part of the Torah.
Usually referring to the Babylonian edition, it is a compilation of Rabbinic law, commentary and analysis compiled over a 600 year period (200 BCE - 427 CE). Talmudic verse serves as the bedrock of all classic and modern-day Torah-Jewish literature.
Jewish Law. All halachah which is applicable today is found in the Code of Jewish Law.
Pertaining to Jewish Law.
Literally means "fit." Commonly used to describe foods which are permitted by Jewish dietary laws, but is also used to describe religious articles (such as a Torah scroll or Sukkah) which meet the requirements of Jewish law.
Laws of Kosher (Jewish dietary laws).
First written rendition of the Oral Law which G-d spoke to Moses. Rabbi Judah the Prince compiled the Mishna in the 2nd century lest the Oral law be forgotten due to the hardships of the Jewish exiles.