Bava Kama 5:7 says

אֶחָד שׁוֹר וְאֶחָד כָּל בְּהֵמָה לִנְפִילַת הַבּוֹר, וּלְהַפְרָשַׁת הַר סִינַי, וּלְתַשְׁלוּמֵי כֶפֶל, וְלַהֲשָׁבַת אֲבֵדָה, לִפְרִיקָה, לַחֲסִימָה, לְכִלְאַיִם, וּלְשַׁבָּת. וְכֵן חַיָּה וָעוֹף כַּיּוֹצֵא בָהֶן. אִם כֵּן, לָמָּה נֶאֱמַר שׁוֹר אוֹ חֲמוֹר. אֶלָּא שֶׁדִּבֵּר הַכָּתוּב בַּהֹוֶה: ‏

Bulls or any other kind of domestic animal are equivalent for the purpose of payment for falling into a pit, the prohibition to go on Har Sinai during Matan Torah, paying double for a thief, returning a lost object, the requirement to unload a fallen animal, the prohibition on muzzling during work, kilayim, and working on Shabbos. And wild animals and birds are also the same. Why does it say "a bull or a donkey"? Because the Torah speaks about the normal case.

(Rashi says something similar about damage caused by an animal on Mishpatim 21:28 and the note on Sefaria says his source is the same Gemara, but I can't find it.)

Some of these halachos apply to all objects, living or not, while some are specific to animals. Do the animal halachos apply to fish?


  • If a shark eats someone, do we apply the normal rules of nezikin from a bull?
  • At some aquariums they have an electric eel tank with a sensor that lights up and tells you how much electricity the eel is producing. My understanding is that the electricity from the eel directly powers the lights. Can you use this on Shabbos?
  • If you hook it up to a food preparation machine with the proper parameters (גידולי קרקע etc.), do you have to set up some kind of contraption that lets the eel eat the same kind of food while it powers the machine?
  • Maybe this should be 2 or 3 separate questions as torts/damages by a shark have nothing to do with electricity generated by eels on shabbos (unless you meant that the eel gives a shock to a bystander)
    – yosefkorn
    Jan 29, 2019 at 14:34
  • 1
    @yosefkorn All of my questions are based on the same premise. The Torah explicitly says certain halachos apply to certain animals (bulls and sometimes donkeys), we derive that they actually apply to all בהמה חיה ועוף, and I want to know if they apply to fish as well.
    – Heshy
    Jan 29, 2019 at 14:41
  • @yosefkorn By the way my focus is not really on the electricity itself. I'm using it because I had trouble figuring out a way for a fish to do melacha deoraisa for a person. An incandescent lightbulb definitely qualifies, regardless of the status of electricity itself.
    – Heshy
    Jan 29, 2019 at 15:19

2 Answers 2


Tosafot Shabbat 55a suggest that the rule forbidding working one’s animals on shabbat would apply to fish as well.

They think that this could be derived from a gezeira shavah linking shabbat to the prohibition of cross-breeding (which the gemara in Bava Kamma 55a definitively rules applies to fish).

Then, say Tosafot, we can learn from shabbat to other areas, such as the prohibition of attaching two different animals to the same vehicle.

(Tosafot also present a different approach, in which the prohibition of cross-breeding and working with different animals would apply to fish, but not necessarily shabbat or other areas.)

  • Interesting! I wonder what melacha they were picturing. I really had to stretch to come up with a melacha that a fish could reasonably do without it being a shinuy, and of course they couldn't have used my electricity example.
    – Heshy
    Jan 29, 2019 at 17:38

In terms of a shark, I'm pretty sure it'd fall under a case of wild animals ALWAYS being considered forewarned. The mishnah in Bava Kamma 15b addresses this, stating:

הזאב והארי והדוב והנמר והברדלס והנחש הרי אלו מועדין רבי אלעזר אומר בזמן שהן בני תרבות אינן מועדין והנחש מועד לעולם

The wolf; the lion; the bear; the leopard; the bardelas, and the snake. These are considered forewarned even if they had never previously caused damage. Rabbi Elazar says: When these animals are domesticated they are not considered forewarned. But the snake is always considered forewarned.

There's a machlokes Rashi vs Tosfos there:

Rashi says these animals are all considered forewarned in terms of biting or any other way it damages

Tosfos says, these animals are ONLY considered forewarned in their usual nature to damage (ex: a wolf tearing apart an animal) but a damaging act that's not in an animals normal nature (ex: a wolf rollerskating into a bed of roses) is not considered forewarned.

Based off Rashi & Tosfos, it would appear that if eating someone or injuring them via biting is in the shark's nature a person would be fully liable.

(for more in depth and some solid lomdus, see here)

  • 1
    This doesn't really answer my question, which is if sharks fall into the category of שור at all even though the language used is בהמה חיה ועוף. If they do, I agree you're probably right.
    – Heshy
    Jan 29, 2019 at 17:43
  • @Heshy that Mishnah lists 5 animals that are all considered מועד מתחילתן. Granted none are from the water, but I assume they’re there to serve as a framework to extend to other types of animals
    – alicht
    Jan 29, 2019 at 17:45
  • I agree. But I don't know if a shark is an "animal" at all for the purpose of this halacha.
    – Heshy
    Jan 29, 2019 at 18:34
  • How are you "using" the electric eel in this example? It hits the sensor and lights the bulb whenever it wishes to, with no human control or intervention over the process whatsoever Jan 29, 2019 at 20:12
  • @JoshK You set it up for the purpose of using its electricity to light the bulb. Maybe you're right and that's not enough human involvement... But you can always come up with a case e.g. you scare it so that it starts electrifying the water.
    – Heshy
    Jan 29, 2019 at 21:24

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .