are sailfish nocturnal
Swordfish have a much wider temperature range, where marlin are more tropical and subtropical in habitat. Another major difference is the dorsal fin on a swordfish is rigid, fixed in the upright position. Whereas all marlins and sailfish have a dorsal fin that can fold down into a channel.Marlins are generally larger than swordfish as well. Swordfish is eaten by humans whereas marlins are generally not.he bill on a swordfish looks just like a sword. A marlin bill is more rounded, not as long, and has a rough, raspy surface that the swordfish does not. They are all large open water predators however, swordfish are primarily nocturnal whereas marlin are diurnal.