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?
Examples:
- 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?