The Torah in Parashat Shemini (Vayikra 11:9) establishes that only fish with both “Senapir” and “Kaskeset” – fins and scales – may be eaten. The fins resemble wings that protrude from the fish’s body, and scales are a series of small discs attached to the fish. The Gemara teaches that every species of fish with scales also has fins; therefore, if scales are seen on the fish’s body, one does not need to look for fins, because a fish that has scales also has fins. Conversely, however, a fish with fins does not necessarily have scales. A fish is considered kosher even if only a single scale is seen on the body. If a species of fish naturally grows scales, then a fish of this species may be eaten even if it is still young and had yet to grow scales by the time it was removed from the water. Additionally, if a fish had scales and they fell off the fish’s body after it was drawn from the water, the fish is nevertheless permissible for consumption. This command applies in all times and places, and to both males and females. The Sefer Ha’hinuch writes that one transgresses this Biblical command by eating a fish without first ascertaining its kosher status. Even if it turns out that the fish was permissible for consumption, nevertheless, one is in violation of this Misva if he eats the fish without first checking to ensure it has scales. As mentioned, once a fish has been determined to feature scales, one does not need to check for fins, because every fish with scales also has fins. But if one ate a fish without first determining that it has scales and is thus permissible, then he has violated this command even if the fish was kosher. The Gemara in Masechet Hulin (66) raises the question of why the Torah bothered to mention that a fish needs fins to be permissible for consumption. After all, once it has scales, then it necessarily has fins, and thus, seemingly, the Torah could have simply said that a fish needs to have scales to be permissible. The Gemara answers that the Torah mentioned also the requirement of fins for the purpose of “Yagdil Torah Ve’ya’adir” – to add more material for us to study. At first glance, this means simply that the Torah added words which were not actually necessary so that we will have more to read and through which to earn reward. The Ritba (Rav Yom Tob of Seville, Spain, d. 1320), however, suggests a different explanation, proposing that perhaps “they, too, cause it to be permissible.” Meaning, it is possible that the presence of both fins and scales on a fish’s body is the reason why that species is considered kosher. Intuitively, we might have assumed that the fins and scales serve merely as a sign indicating to us that this species is permitted by the Torah for consumption. The Ritba, however, suggests that perhaps these features are not the indicators of a fish’s kosher status, but the cause, or reason, for the fish’s kosher status. While we do not understand why, G-d instructed that these properties are what make a fish kosher and permissible for us. If these properties were only indicators that a species is kosher, then it would suffice for the Torah to mention only scales. But since these properties are the reason why a fish is kosher, the Torah mentioned both to teach us this very point – that the presence of both fins and scales makes a species permissible for consumption, that for reasons that we cannot understand, these features elevate a fish’s status, making it worthy of being consumed.