To not eat impure fish: To not eat impure fish, as it is stated (Leviticus 11:11), “you shall not eat of their meat and you shall abominate their carcasses.” And we have written the signs of the fit (kosher) fish in the positive commandment (Sefer HaChinukh 155) — which is to check the signs of the fish — which we have counted in the tally [of the commandments] in deference to Rambam, may his memory be blessed.
That which we wrote above regarding the matter of the prohibition of foods (Sefer HaChinukh 73) is from the roots of the commandment — that God, blessed be He, distanced all in which injury is found from His people, whether beast, fowl or fish, from the reason that we said there.
And [it] is practiced in every place and at all times by males and females. And one who transgresses it and eats a kazayit of an impure fish is lashed; and inadvertently, is exempted.
שֶׁלֹּא לֶאֱכֹל דָּג טָמֵא – שֶׁלֹּא לֶאֱכֹל דָּג טָמֵא, שֶׁנֶּאֱמַר (ויקרא יא יא) מִבְּשָׂרָם לֹא תֹאכֵלוּ וְאֶת נִבְלָתָם תְּשַׁקֵּצוּ. וְסִימָנֵי דָּגִים כְּשֵׁרִים כְּתַבְנוּם לְמַעְלָה בְּמִצְוַת עֲשֵׂה (מצוה קנה) שֶׁהִיא לִבְדֹּק בְּסִימָנֵי דָּגִים שֶׁחָשַׁבְנוּ מִן הַמִּנְיָן לִכְבוֹד הָרַמְבַּ"ם זִכְרוֹנוֹ לִבְרָכָה.
To not eat impure fish: To not eat impure fish, as it is stated (Leviticus 11:11), “you shall not eat of their meat and you shall abominate their carcasses.” And we have written the signs of the fit (kosher) fish in the positive commandment (Sefer HaChinukh 155) — which is to check the signs of the fish — which we have counted in the tally [of the commandments] in deference to Rambam, may his memory be blessed.
מִשָּׁרְשֵׁי הַמִּצְוָה. מָה שֶׁכָּתַבְנוּ לְמַעְלָה (מצוה עג) בְּעִנְיָן אִסּוּר הַמַּאֲכָלוֹת שֶׁהָאֵל בָּרוּךְ הוּא הִרְחִיק מֵעַמּוֹ כָּל מָה שֶׁנֶּזֶק נִמְצָא בּוֹ, הֵן בְּהֵמָה אוֹ עוֹף אוֹ דָּגִים, מִן הַטַּעַם שֶׁאָמַרְנוּ שָׁם.
That which we wrote above regarding the matter of the prohibition of foods (Sefer HaChinukh 73) is from the roots of the commandment — that God, blessed be He, distanced all in which injury is found from His people, whether beast, fowl or fish, from the reason that we said there.
דִּינֵי הַמִּצְוָה. כָּתַבְנוּ לְמַעְלָה גַּם כֵּן, וְהֵם בְּחֻלִּין פֶּרֶק שְׁלִישִׁי [י"ד סי, פ"ג]
We have also written the laws of the commandment above, and they are in Chullin, Chapter 3. (See Tur, Yoreh Deah 83.)
וְנוֹהֶגֶת בְּכָל מָקוֹם וּבְכָל זְמַן בִּזְכָרִים וּנְקֵבוֹת. וְעוֹבֵר עָלֶיהָ וְאָכַל כַּזַּיִת מִדָּג טָמֵא בְּמֵזִיד, לוֹקֶה. בְּשׁוֹגֵג, פָּטוּר.
And [it] is practiced in every place and at all times by males and females. And one who transgresses it and eats a kazayit of an impure fish is lashed; and inadvertently, is exempted.