Chullin 27b: Animals were created from earth, so they need both the esophagus and windpipe cut. Fish were created from the water, so they don’t require any shechitah. Birds were created from the mud, so they only need one tube cut.
Rema Yoreh Deah 13:1: It is allowed to cut a piece off a live fish and eat it, but it is forbidden to eat a whole fish live because of the prohibition, “Do not make yourself disgusting.”
חולין כז ע”ב: דרש עובר גלילאה: בהמה שנבראת מן היבשה ־ הכשרה בשני סימנים, דגים שנבראו מן המים ־ הכשירן בולא כלום, עוף שנברא מן הרקק ־ הכשרו בסימן אחד.
יורה דעה יג,א בהמה חיה ועוף טעונין שחיטה דגים וחגבים אין טעונין שחיטה: הגה ומותר לאוכלם מתים, או לחתוך מהם אבר ולאכלו, אבל אסור לאכלן חיים משום בל תשקצו.
The Hamodia newspaper recently interviewed Rabbi Boruch Cohn, a rebbi in Lakewood who enjoys fishing in local lakes and streams. Their first question was, “Fishing is not known to be a popular downtime activity in our circles. Is there a good reason for this?”
Rabbi Cohn replied, “I don’t have a clear answer to this one, but it might be that people don’t have the time or perseverance to fish; it’s not a pastime for those who want instant gratification! Another reason could be that they’re prone to associate it with hunting, which is assur. When I was thinking of taking up fishing, I discussed the issue with Dayan Yaakov Posen, shlita, of Washington Heights, where I grew up. He advised me that the issur of tzaar baalei chaim (causing affliction to living things) does not apply to fish and gave me an enthusiastic go-ahead. I have since spoken to several Lakewood poskim on this matter, and they are in full agreement with Dayan Posen.”
(Hamodia, July 8, 2020, Community p. 25)
[Actually, the problem with hunting, according to the Noda Beyehuda (Tinyana YD 10, brought in Pischei Teshuva YD 28:10), is not tzaar baalei chaim, for two reasons:
1) People use the skins, and there is no prohibition on tzaar baalei chaim when the animal is used for the needs of man. The source for this is Piskei Hatosafos Avodah Zarah 11a, explaining why it is allowed to cut the hooves of the king’s horses after the king dies.
2) There is no prohibition of tzaar baalei chaim when you are killing the animal, only when you are keeping it alive and suffering. This is based on Chullin 7b, where Rabbi Pinchus ben Yair reprimanded Rebbi for owning dangerous white mules. Rebbi proposed cutting their hooves, but Rabbi Pinchus responded that this would be tzaar baalei chaim. Then Rebbi proposed killing them, to which Rabbi Pinchus responded that it would be bal tashchis – wastefulness. From this exchange we see that killing can never be tzaar baalei chaim.
Rather, the problem with hunting is that killing animals for sport is cruelty. We are enjoined to feel that “His mercies are upon all His creatures” and that is why we don’t say bless someone who buys a new leather garment that he should wear it out and buy a new one (Rema Orach Chaim 223:6). Therefore hunting, unless done for a living, may not be strictly forbidden but it does inculcate a bad midah and is not the right thing for a Jew to do.
Furthermore, going out to the forests where the wild animals live is dangerous, and one is forbidden to place his life in danger. Esav was an expert hunter, yet he testified on himself, “Behold I am going to die,” and the Ramban explains that he was likely to die in his father’s lifetime, so he did not need the birthright. One who hunts to make a living is permitted to risk his life, as it says, “He risks his life for it” (Devarim 24:15). But if he doesn’t need the money, it is forbidden.
According to this, it would seem that fishing for sport should exemplify the same bad midah of cruelty as hunting for sport. Tzaar baalei chaim may not apply, but the midos argument still would.
The Noda Biyehuda’s contention that there is no prohibition of tzaar baalei chaim when killing the animal would seem to be against the Sefer Hachinuch 451, who says that the reason for slaughtering at the neck with a perfectly sharp knife is in order to minimize tzaar baalei chaim. According to the Chinuch, we could prove that the prohibition does not apply to fish from the very fact that no shechitah is required.
The nafka minah between the Noda Biyehuda and the Chinuch would be in the question of whether one may make a fish suffer when not killing it. According to the Noda Biyehuda it is forbidden, while according to the Chinuch it is permitted.
Rabbi Menashe Klein (Mishneh Halachos 6:216) was asked whether someone who has an aquarium in his house is obligated to feed the fish before eating a meal. The questioner had brought proof from the fact that one may cut a piece off a live fish, that there is no prohibition of tzaar baalei chaim on fish. R’ Menashe counters that perhaps there really is tzaar baalei chaim on fish, yet eating from a live fish is allowed because the prohibition on causing pain doesn’t apply when using the animal for human needs. We see, for example, that one may cut off and eat a piece of a ben pekuah (a live baby found inside a slaughtered cow) even though it is alive and certainly feels pain (Taz YD 13:3).
Then he brings a proof that there is indeed tzaar baalei chaim on fish, from the fact that one may not harness two different kinds of fish to his boat (Bava Kama 55a). The prohibition on harnessing two different species is because of tzaar baalei chaim, since an animal does not like to work together with a different kind of animal (Chinuch 550). If this applies to fish, then clearly there is tzaar baalei chaim on fish. He concludes that one must feed his fish before eating a meal (and therefore recommends not keeping an aquarium, lest one transgress this prohibition when eating away from home).
Thus there appears to be an internal contradiction in the Chinuch. If fish have tzaar baalei chaim, then why is it allowed to eat them without shechitah? And you cannot answer, as R’ Menashe Klein does, that for the purpose of man there is no prohibition, because the Chinuch says that even at the time of shechitah we try to minimize pain.
Rather, the answer is probably that the Chinuch’s approach is merely to suggest reasons for mitzvos (often, as in these two cases, more than one reason for each mitzvah), without being particular that everything he says leads to the same halachic conclusions.]