The great barracuda, unlike some of its close relatives, is not generally considered a nocturnal species. There seem, however, to be interesting exceptions to this rule, as one might expect from an eminently opportunistic predator. Solitary and grouped great barracuda have been seen moving purposefully through the water on nights when the moon is at or near Full Moon, possibly taking advantage of the light conditions to extend their hunting beyond sunset. Dr James Porter, of the University of Georgia, once saw a small school of large barracuda moving across the water above him during a lightning storm one night near Molasses Reef in the Florida Keys, that is an extremely unusual case.

Generally great barracuda seem to rest during the night — divers' lights can awaken them and they usually avoid the light if it is trained on them. One should be considerate, bearing in mind one's own probable reactions to being woken up by a blinding light being directed into one's eyes, for the barracuda may charge the light. Dr Walter Starck, who conducted a lengthy (and groundbreaking) study of the nocturnal activity of fishes at Alligator Reef in the Florida Keys, recounts one instance where a great barracuda was so startled by divers' lights that it accelerated into a portion of the reef and was killed.