Rabbi Yakov Haber
Guide to the Piscatorially Perplexed
Among the laws of kosher species outlined in parashas Shemini, those pertaining to fish are unique. Both kosher beef and fowl require kosher slaughter (Rambam Hilchos Shechita 1:1), their blood is prohibited (Hilchos Ma'achalos Asuros 6:1), and both are subject to the prohibition of eiver min hachai, forbidding the consumption of the flesh severed from a live animal (ibid. 5:1). Domestic cattle is additionally subject to the prohibition of cheilev, forbidden fat, (ibid. 7:1), and all kosher animals must have the gid hanashe removed (ibid. 8:1). In stark contrast, fish are subject to none of these restrictions; in the language of the Talmud (Kerisos 21a-b), "kulo heter - it is entirely permitted". Contrary to a minority view in the Rishonim which maintains that "asifa" - taking the fish out of the water alive is required as a parallel to shechita (see Magid Mishne to Hilchos Shechita 1:3 quoting Rav Sa'adia Gaon), the accepted view is that fish require no ritual act at all to permit their consumption; even if removed dead from the water, they are still permissible (Rambam ibid.). What lesson can be learned from these unique halachos?
The mystery deepens when we consider these other facts concerning creatures of the sea. According to the Talmud (Sanhedrin 108a cited by Rashi to Noach 7:22), the fish did not perish during the Great Flood in the days of Noach. For this reason, there was no reason to take them onto the teiva to be saved (Ramban ibid. 23). Whereas the commentaries note that the Torah generally prohibits us from consuming animals and fowl which are torefim - those which prey on other creatures, no such restriction exists concerning fish. As long as a given sea creature has fins and scales, it is rendered kosher. Indeed, many popular kosher fish (e.g. flounder and bass) eat other fish. The popular tuna fish is a voracious carnivore devouring hundreds of other fish daily.
Before Adam and Chava sinned by partaking of the fruit of Eitz HaDa'as Tov v'Ra, they were only permitted to eat vegetation, not animals (Bereishis 1:29). The same was true concerning the Divinely implanted nature of animals - they would only eat vegetation (ibid. 30). After the Mabul, Noach and his descendants were permitted to eat animals (Noach 9:3). Even though the Torah does not specifically state that animal nature also changed, it clearly did as well. However, as noted by Oznayim LaTorah (Bereishis 1:29), the absence of a statement concerning the permitted diet of sea creatures implies that many fish were always carnivorous both before and after the Mabul. All of these differences certainly require analysis.
Perhaps we can suggest an approach giving one insight into the mystery of the denizens of the sea. With only occasional manifestations of its existence, sea life occurs hidden from the human senses. The seemingly lifeless waters of the ocean, lakes and rivers hide the lively activity of its millions of inhabitants (see Rav S.R. Hirsch to VaYechi 48:16). Furthermore, all of their residents highly depend on the aquatic environment for survival, most of them utilizing water for the very breath of life. The life-sustaining quality which the waters of the seas provide its inhabitants is only noticeable when one cares to take notice - to study its depths.
In the famous analogy of the fox and the fish given by R' Akiva (Berachos 61b), water represents the life-giving and life-sustaining nourishment of Torah. This ultimate truth that our connection to our Creator as manifested through the Torah is what really gives us life rather than a series of biological processes requires diligent study and reflection; it is not immediately manifest unless one thinks deeply about the world and its true nature, just as a student of the sea must reflect on its nature which is not immediately apparent. Mankind, living in a world of confusion and hiddenness - a world in which a different narrative of existence seemingly and tantalizingly presents itself, a narrative in which the purely physical reigns supreme, a narrative of "survival of the fittest" of "eat or be eaten", a narrative indicating that the mighty and the wealthy have ultimate power - is called upon to "reveal the mask", to realize that O-L-A-M is rooted in the word heleim, hiddenness. The individual is challenged to look beneath the surface of the "sea" of the world, deeper into the true Reality of Existence, that the complex web of animal life, the rules of nature, economic success and failure, marriage, family, careers, goals, aspirations and their fulfillment are all only tools with which to achieve the ultimate goal - cleaving to G-d via His Torah. Therefore the world in which we live is a world where careful restrictions and boundaries must be legislated by the Creator to train humanity in general, and more specifically the Jewish people as the teachers of mankind, that the world has a Creator and Legislator. Only He determines how the world is to be utilized and for what purpose. Therefore, initially, Man was only permitted to partake of part of the word, its vegetation. Even later when the consumption of animals was permitted, this consumption is informed by many complex halachos - shechita, eiver min hachai, dam, cheilev, gid hanashe, and more. The world of the sea, by contrast, representing in a sense a truer reality, a world in which dependency on the water and its analogy to Torah is more manifest, is a world not requiring all the restrictions to highlight man's limited control. Hence, fish are "kulo heter".
We should not be surprised then that talmidei chachamim in the analogy of the Zohar (Shemini 42a) are compared to fish, recognizing as they do this true Reality. The Midrash (Bereishis Rabba 97) comments, "Even though fish live and grow in the water, when a drop of rain falls, they receive it with great thirst as if they never tasted water before. So too, the people of Israel grow in the waters of Torah, but when they hear a new Torah insight, they receive it with zest!" The Zohar (ibid.) even uses the analogy of one fish swallowing another to illustrate one talmid chacham being "victorious" over another - who has not mastered Torah properly and yet rules in matters of Torah law incorrectly - by proving the latter's view to be incorrect.
This fundamental truth of the purpose of the world was immutable even though the sinners of the generation of the Mabul refused to lead their lives by its implications. Hence, the fish, representing this deep, unchanging truth were not destroyed. Similarly, the fish never needed the directive to initially limit their diet to vegetation only.
Perhaps based on this approach we can suggest an insight into the kosher signs of fish. The scales represent armor or defenses similar to a coat of mail which is called, "kaskasim" (Shmuel 1 17:5), and the fins represent mobility or functionality. Chazal teach us, "kol sheyeish lo kaskeses, yeish lo s'napir" (Nidda 6:9 quoted in Chulin 66b) but not the opposite. All scaled fish have fins, but not all finned fish have scales. Perhaps the message is that only one with armor, protecting the precious truth of the Reality of the world can function properly in the world. This is notwithstanding the fact that there are many who seemingly function in the world deluding themselves into thinking that they are living Reality - v'yeish sheyeish lo s'napir v'ein lo kaskeses, some have fins but no scales; they operate in the world without the necessary protection and correct outlook.
Shabbos kodesh represents mei'ein Olam HaBa, a time in the week when we reconnect to the true dimension, to the World of Eternity, of communion with Hashem toward which this world is directed. The whole week is infused with its holiness and draws from its reservoirs. Perhaps for this reason there is an ancient custom to eat fish on Shabbos - basar v'dagim v'chol matamim (see Mishna Berurah 242:2 and Beiur Halacha ibid. s.v. "zeicher"). May we all merit to absorb the message of the sea, of constantly sanctifying all aspects of the world to connect to our Ultimate Source.
 See commentaries to Isaiah (11:6-7), Rambam Hilchos Melachim (12:1), Ra'avad and commentaries there, and Ramban to Noach (9:5) and Bechukosai (26:6).