Of all that move in the waters. — That is, apart from the fishes exhibiting the above-named signs, all other inhabitants of the water are forbidden. Hence all shell-fish, whether molluscs or crustaceans, and cetaceous animals, are unclean.
Related Commentaries of Leviticus 11:10
Leviticus 11:10
10 And all that have not fins and scales in the seas, and in the rivers, of all that move in the waters, and of any living thing which is in the waters, they shall be an abomination unto you: