(Ibid. 18) "which is in the waters beneath the earth." To include reflected images. These are the words of R. Akiva. Others say: To include shavririm (water creatures). So far did the Holy One Blessed be He pursue the yetzer hara (the evil inclination) to give it no pretext for permissiveness (in this area).
Rabbi Akiva Interpreted This to Include Even Reflected Images
Mekhilta Tractate Bachodesh 6:16