Do Fish Require a Matir?
The gemara in Chullin contrasts different types of edible livestock, each of which requires a form of shechita, as opposed to fish, which do not require classic shechita. The gemara's initial language implies that while fish do not require shechita, they do require a parallel action to shechita to render them mutar to eat. As the gemara articulates, "Ba-asifa be-almah sagi" – collecting fish from water even without performing an act of shechita is sufficient. Subsequently, the gemara articulates the lack of a need for shechita for fish in a different fashion: “Fish…are permissible to eat without any action.” This implies that NO formal action is necessary to render a heter to eat them.
The question as to whether fish require a shechita-like action to create a heter or are permissible even without a shechita-like action may affect several interesting questions.
It appears that the Rambam rules that fish-like livestock require “collection,” which parallels the act of shechita as a “matir.” In Hilkhot Shechita (1:3), he writes: "Asifatam hi ha-materet otan.” This reinforces the notion that the act of COLLECTING the fish from water functions in the capacity of shechita in permitting the fish to be eaten. By contrast, the language of the Rashba in his Torat Ha-Bayit suggests that a fish does not require any act of matir, but is rather naturally permitted to be eaten. The simple reading of the Tosefta in Terumot certainly supports the Rashba's position: “All fish may be eaten as they are, whether alive or dead.”
An interesting consequence of this question regards the case of fish that were not collected from water while alive but died naturally. The Rambam clearly permits these fish; even though he requires an act of collecting, he does not distinguish between collecting live fish and dead fish. As long as the fish were drawn from water, they can be eaten. By contrast, R. Sa'adia Gaon (at least his position as it appears in the Kessef Mishna) prohibits fish that died in water. Obviously, R. Sa'adia Gaon believed that an act of drawing is necessary AND that this act must resemble shechita in terminating life. Thus, if the fish died prior to that act, it is forbidden. The Rambam appears to agree that an act of collecting is necessary, but this act can be performed upon a dead fish as well.
Two interesting gemarot may support the idea that the collecting is actually the matir of fish in the same manner that shechita acts as the matir of meat. The gemara in Chullin (75a) discusses the precise moment at which fish meat begins to receive tuma if touched by a tamei item. Usually, live items cannot contract tuma, and we would therefore expect fish meat to receive tuma only after the fish dies. Beit Shammai rules, however, that fish meat is capable of contracting tuma from the time that the fish is captured. Presumably, Beit Shammai views the act of collecting or catching a fish as creating a heter to eat the fish, and consequently as imposing the status of “ochel” (food) upon the fish. Once it receives the status of ochel, the fish meat can contract tuma. (See the sefer Shiurei HaRav on Massekhet Chullin, p. 100, n. 169, where R. Menachem Genack is recorded as making this point in the name of R. Soloveitchik.)
A second gemara that may indicate that collecting the fish is considered a matir is found in Chullin 76, which records a debate regarding the simanei kashrut, the body-signs that determine whether a fish is kosher. The gemara questions whether a fish that loses its signs when drawn from the water is kosher. Ultimately, the gemara rules that it is, but the very question suggests that the act of drawing a fish from water confers the heter upon the fish. Conceivably, if the fish were to lose its simanei kashrut at this stage, the process would fail. While the gemara rejects this idea and permits fish that lose their signs when drawn from the water, the question itself may reflect the position of the Rambam that the act of collecting is considered a matir.
A third gemara reflects the Rashba's position that a fish does not require a matir. The gemara in Chullin (77b) prohibits worms that are found between the skin and flesh of a recently shechted animal. However, the gemara permits the consumption of worms found between the skin and flesh of a fish. Distinguishing between the two, the gemara asserts that the worms in an animal are not affected by the shechita on the host animal. Absent of the act of shechita as a heter, these worms remain forbidden to eat. By contrast, worms in a fish, like the fish itself, DO NOT REQUIRE an act of matir and therefore are permitted to eat. This gemara certainly implies that a fish (and its resident worms) do not require an act of matir in the manner that livestock meats require an act of matir.