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Swordfish

The swordfish (Xiphias gladius) is a large, elongated, and scaleless fish found in warm and temperate oceans globally. It is the sole member of the family…

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Illustration of a swordfish (Xiphias gladius) with a long, pointed bill, streamlined body, tall dorsal fin, and a forked tail, shown in profile against a white background.
Swordfish (Xiphias gladius) © Painted especially for <em>Encyclopaedia Britannica</em> by Tom Dolan, under the supervision of Loren P. Woods, Chicago Natural History Museum

What is swordfish?

The swordfish (Xiphias gladius) is a large, elongated, and scaleless fish found in warm and temperate oceans globally. It is the sole member of the family Xiphiidae and is highly valued as both a food source and a game fish.12

Key characteristics include:

  • The Sword: A flat, long sword extending from its snout, which the fish uses to slash at prey. This feature has earned it the nickname “broadbill”.1
  • Physical Appearance: It features a tall dorsal fin, lacks teeth, and has no pelvic fins. Its coloration is typically purplish or bluish on the upper body and silvery below.1
  • Size: It can reach a maximum length of approximately 4.6 meters (15 feet) and weigh up to 450 kilograms (1,000 pounds).1

Unlike marlins and other spear-nosed species, the swordfish’s “sword” is distinctively flat rather than rounded.1

perciforms
Representative perciforms of the families Stichaeidae, Blenniidae, Anabantidae, Anarhichadidae, Acanthuridae, Belontiidae, Scombridae, Xiphiidae, and Istiophoridae. Image: Encyclopædia Britannica, Inc. / Encyclopædia Britannica

How does the swordfish use its bill to hunt?

The swordfish (Xiphias gladius) utilizes its distinctive, flat bill—often referred to as a sword—primarily as a weapon to slash at schools of prey fish. By swinging this elongated snout through the water, the swordfish injures or stuns its prey, making them easier to capture and consume.1

What makes the swordfish different from a marlin?

While both the swordfish and the marlin are well-known billfish, they possess distinct anatomical differences that set them apart:

  • Shape of the Bill: The most notable difference is the shape of the snout. The swordfish has a flat, broad bill, which is why it is often called a “broadbill.” In contrast, marlins and other spear-nosed fishes possess a rounded, spear-like bill.1
  • Pelvic Fins: The swordfish is distinguished by a complete lack of pelvic fins, whereas marlins possess them.1
  • Teeth: Adult swordfish are toothless, a feature that differentiates them from many other billfish species.1
  • Scales: The swordfish is a scaleless fish, while marlins typically have scales.1

In which parts of the ocean are swordfish typically found?

Swordfish (Xiphias gladius) are widely distributed across the globe. They are typically found in warm and temperate oceans throughout the world.1

Sources

  1. swordfish — Encyclopædia Britannica
  2. swordfish — Merriam-Webster

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