Bechorot 4-10: A Non-Kosher Fish Inside a Kosher One
by R. Gidon Rothstein
A Mishnah on Bechorot 7b considers fish that swallow fish. A swallowed kosher fish remains kosher despite being inside a non-kosher one, and, in reverse, a swallowed non-kosher fish remains non-kosher. In this latter case, the Mishnah adds “because it was not grown by it,” a phrase it did not add in the first case. Studying the codification of the issue draws us to other halachic questions I hope you will find interesting.
Rambam, Laws of Forbidden Foods 1;5 has the Mishnah pretty much as is, except he speaks of a fish “found in” another fish. Maggid Mishneh explains that the Gemara originally thought these rules require us to have seen the fish being swallowed, but R. Ashi tells us any other scenario for finding one fish inside another is unlikely enough to allow us to assume it was swallowed. Hence found, even if we didn’t see the event.
Where In the Fish
Tur Yoreh De’ah 83 adds a consideration, whether it has to be found in the digestive tract, or even on the way to being eliminated. For the non-kosher fish, finding it whole shows it has not been digested (had it been digested, he implies, it would become part of the kosher fish).
Shulchan Aruch has it that way as well, 83;9-10. Taz points out they both omitted a case the Gemara raised, an embryo with the appearance of a kosher fish in a non-kosher fish’s reproductive tract (the Gemara thought kosher fish laid eggs for the male to fertilize, where non-kosher fish spawned live young, as a Google search tells me happens with cartilaginous and bony fish; for these latter, there is an ovarian duct or uterus).
They ignored the case, Taz explains, because of how rare it would be, given the idea of R. Ashi we saw earlier, most fish reproduce in their image. A side note: when Aruch HaShulchan records Taz’s idea, Yoreh De’ah 83; 51-2, he phrases it with a twist, since most fish spawn fish in their own image, we have no doubt it was swallowed rather than home-grown.
A different take on how majorities affect our worldview. At least in this case, he is saying it is so unlikely, we are certain. Leaving no doubt.
Does It Get Absorbed?
As for the excretory system, Shach 83;31 wonders why it was spoken of so generally; if the swallowed fish had actually been excreted, he is sure it should no longer be prohibited, because it’s fully digested and no longer counts as the original fish. He is sure they were relying on the language of “found in” to limit this to where it was still in the host fish’s body.
Aruch HaShulchan takes up the question, too, wondering why the kosher fish swallowed by a non-kosher one isn’t considered to have been fully absorbed into the host’s body. He argues (in contrast to donkey urine, not our topic), as long as the fish remains whole, it has not yet been changed or affected by the host fish.
Though twenty-four hours counts for digestion in the context of tum’ah, of the realm commonly called ritual impurity, the rules for kashrut differ. He does know (but does not accept) those who think an eaten fish would no longer be considered itself if it had been chewed up.
Finally, he disagrees with Shach, if excreted whole, it’s still itself, kosher or non-kosher. Having passed through a fish, unchewed, does not change it from what it was.
Trusting Jews and Non-Jews
That’s the halachic takeaway from the sugya in Bechorot. Kind of short. As it happens, the previous paragraph in Shulchan Aruch, 83;8, raises an issue I always find interesting, whom we trust about the kashrut of food. The topic is fish eggs that have the requisite kosher look, one side rounded, the other more pointed. If the Jew selling them reports s/he took them from a kosher fish him/herself, we are allowed to trust him/her.
If the seller says they’re kosher, without further details, we can only trust someone with an established reputation for honesty in these situations. However, by SA’s time, widespread custom had Jews buy eggs (fish or not), even from non-Jews, as long as they were the color of kosher ones.
The required standards are not quite clear. Taz, 83;12, thought Beit Yosef’s note, earlier authorities had clearly investigated the issue and found that no non-kosher eggs had that color, was what allowed for it. Peri Megadim qualified the point, because Beit Yosef in fact said some non-kosher eggs have the color until we salt them, in which case this custom only allowed buying salted such eggs.
Nor, adds Peri Megadim, could we use this sign to allow something like a dag barbot”a, because it is not so clear a sign as to override the other issues pointing to this fish being non-kosher. [A Google search says this is the Atlantic bearded brotula, a non-kosher fish.]
AH 83;50 notes later authorities [Peri Chadash and others] who recoiled from such a leniency regarding a Biblical prohibition. He agreed with them, thought we may not eat fish eggs transported over distance without any kind of supervision. In the same paragraph, though, he knows and accepts the possibility of drinking a fish-based medicine, not only for those actively ill, because it was well-known to be made only with kosher ingredients.
Shach 83;26 brings us back to the issue of trust. Someone huchzak be-kashrut, has a well-established reputation of trustworthiness, we don’t need to ask, we can simply buy fish eggs or embryos s/he is selling, whole or mashed up, unless s/he makes an obviously false claim.
Some of the questions that can arise with buying fish, in a world without assiduous kashrut organizations.