A swordfish also has a much more elongated body with multiple pectoral fins, while the latter has a cylindrical body with a single dorsal fin. Moreover, a marlin’s pelvic fins are hardly visible, whereas a swordfish’s pectoral fins are conspicuously visible. Hence, the most potent difference between these two varieties of billfish can be noted with regard to their dorsal fin shapes and pectoral fin visibility.
Swordfish vs Marlin
The main difference between swordfish and marlin is that the dorsal fin of a swordfish bears a close resemblance to a shark’s tail, while the single dorsal fin of a marlin tapers down into a low ridge along the body of the fish. Swordfish bears a distinctive feather-like appearance, while marlin’s dorsal fin lacks such distinction.