Sentence:  It was all genuine footage of various kinds of ray-fish: first a manta gliding just below the surface of a purple sea near the coast of Argentina. He glided there amongst the light beams that penetrated the water like daggers stabbing into it, while <WSD>remorae</WSD> skirted among his wing-fins. 
Meaning of the word marked with <WSD> tags:  Any of various elongate fish from the family Echeneidae, the dorsal fin of which is in the form of a suction disc that can take a firm hold against the skin of larger marine animals. (from mid 16th c.)