To find the kashrus status of an organism, we first need to correctly classify it as plant, animal, bird, or asher bamayim*, as each group has its own distinct requirements. E.g., animals need to chew cud and have cloven hooves, while asher bamayim need (fins and) scales.

What is the halachic definition of asher bamayim (אשר במים)?

* This is how the Torah calls water-living creatures. Rabbinical writings use the word dag (דָג).

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    Should your list include "bug"? Should all of the terms be in Torah-Hebrew (or, better yet, in both Torah-Hebrew and English-in-quotes)?
    – Isaac Moses
    Commented Dec 11, 2014 at 20:17
  • Let us continue this discussion in chat.
    – Adám
    Commented Dec 11, 2014 at 20:22
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    I believe Hullin discusses the classification of a seal and concludes that you can tell where its from by testing where it runs when it is afraid.
    – Baby Seal
    Commented Dec 12, 2014 at 20:14
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    @sabbahillel Appears? Did you see my picture of a dolphin?
    – Adám
    Commented Dec 14, 2014 at 15:34
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    No where in the Parsha that discusses fish does it say the word Dag. > את זה תאכלו מכל אשר במים, כל אשר לו סנפיר וקשקשת במים בימים ובנחלים > אותם תאכלו. וכל אשר אין לו סנפיר וקשקשת בימים ובנחלים מכל שרץ המים > ומכל נפש החיה אשר במים , שקץ הם לכם. ושקץ יהיו לכם, מבשרם לא תאכלו ואת > נבלתם תשקצו. כל אשר אין לו סנפיר וקשקשת במים, שקץ הוא לכם This would seem to indicate that any water living creature requires fins and scales to be Kosher, and that would be the case even if it is not a fish. Commented Dec 15, 2014 at 19:03

1 Answer 1


A preliminary answer: according to the Aruch Hashulchan (Y.D. 83:10) the sea-creatures (i.e. fish) that are permitted by the Torah are only those that are fish-like, in that they have bones and proliferate. Additionally, he writes that sea-creatures which look like land animals - even if they have fins and scales - are not included in the kosher כל אשר יש לו סנפיר וקשקשת במים.

Simply speaking, the Torah really means to include everything living in the sea. This is implied by the Ramban on Vaykira 11:10 who includes sea creatures with legs like those of land animals, and the Vilna Gaon (Keilim 10:1) that says that the Torah gives all sea-creatures have the same halakhic status, seemingly in all matters.

If צפרדעים are frogs, then my inclination would be to say that they too are sea-creatures despite being amphibious (based on Shemos 7:28) but I have no source

  • +1, but can you maybe clarify the language a bit? The first paragraph seems to imply that jellyfish, squids, and crustaceans are not "asher bamayim", but the second seems to contradict.
    – Adám
    Commented Jan 30, 2015 at 15:20
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    @NBZ I think that they disagree (hence 'contradict'), but I don't really understand the Aruch Hashulchan Commented Jan 30, 2015 at 15:23

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