Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 179
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 179, with English translation by Maimonides (Rambam).
שלא לאכול שרץ המים, שנאמר "אל תשקצו, את נפשותיכם, בכל השרץ" (ויקרא יא,מג).
Not to eat swarming creatures that breed in the water, as [Leviticus 11:43] states: "Do not make yourselves detestable [by eating] any swarming creature."