It has a long, pointed head, measuring 17–18% of the standard length, and a large mouth with the lower jaw protruding beyond the upper.

[4][5] Adult snake mackerels conduct a diel vertical migration, staying in deeper water during the day and rising to the surface at night to feed.

The young and juveniles also migrate vertically but in the opposite direction, staying near the surface during the day and moving deeper at night.

[7] The snake mackerel is caught as bycatch in the tuna longline fishery and is of minor commercial importance.

King Kamehameha was apparently not fond of it, as he once remarked that it is a "delicious fish for the back country people", meaning fine for those who could not obtain anything better.

[8] A night-time encounter with Gempylus species in the open sea is described by Thor Heyerdahl in the accounts of the Kon-Tiki expedition.

Later Thor Heyerdahl notes: "Only the skeleton of a fish like this one had been found a few times on the coast of South America and the Galapagos Islands; ichthyologists ... thought it lived at the bottom of the sea at a great depth, because no one had ever seen it alive.