What Is The Difference Between Swordfish and Marlin?

What is the difference between swordfish and marlin? Swordfish has a dorsal fin more like a shark’s and it extends far up looking like a feather while marlins have a single dorsal fin that connects along the fish’s back to a short soft-looking ridge.

Swordfish and marlin are both members of the billfish family. The family comprises members that have sword-like bills. The billfish family comprises swordfish, marlins, and sailfish. Both can grow up to 14 feet long. They are both large as swordfish can grow up to 450 kilograms while marlins can grow up to 680 kilograms.

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Difference Between Swordfish and Marlin With Table

Characteristics Swordfish Marlin
Appearance They have more rounded bodies. They have long, tubular bodies.
Weight It can weigh up to 450 kilograms. It can weigh up to 680 kilograms.
Snout Their snout is long and flat. They have smooth and round snouts.
Dorsal fin Their dorsal fin resembles more of a shark’s extending far up looking like a feather. They have a single dorsal fin that connects along the fish’s back to a soft-looking ridge.
Pectoral fins They are more visible. They are barely visible.
Taste Their flesh has a high flavor. Their flesh has a mild flavor.
Lifespan They live up to 15 years. They live up to 20 years for males and 30 years for females.

What is Swordfish?

Swordfish is a large, predatory fish known for its distinctive appearance and delicious, firm-textured flesh. Scientifically known as Xiphias gladius, swordfish are popular in culinary traditions around the world. Here’s a detailed definition and explanation for better understanding:

Physical Characteristics

  • Size: Swordfish are among the largest of all bony fish. They can grow to impressive sizes, with adults typically ranging from 6 to 11 feet (1.8 to 3.4 meters) in length.
  • Distinctive “Sword”: One of the most prominent features of swordfish is the elongated, sword-like bill extending from the front of their upper jaw, giving them their name. This “sword” can be as long as one-third of their body length.
  • Coloration: Swordfish have a streamlined body with dark blue-black or brownish-black skin on their upper side, fading to a lighter color on their belly.

Habitat and Distribution:

  • Oceanic Species: Swordfish are primarily found in the world’s oceans, inhabiting both warm and temperate waters. They are known to swim at various depths, from the surface to deeper waters.
  • Global Range: They have a wide distribution and can be found in the Atlantic, Indian, and Pacific Oceans.

Diet and Feeding Habits:

  • Carnivorous Predators: Swordfish are carnivorous and are apex predators in their ecosystems. They feed on a diet of various fish species, squid, and occasionally crustaceans.
  • Hunting Technique: They are known for their powerful bursts of speed when hunting prey, often slashing at schools of fish with their sword-like bill.

Life Cycle:

  • Reproduction: Swordfish reproduce by laying eggs, with females producing large quantities of tiny eggs. After hatching, young swordfish larvae go through several developmental stages before maturing into adults.
  • Growth: Growth rates are variable, but swordfish can reach maturity at around 4 to 5 years of age.

Culinary Significance:

  • Dining Delicacy: Swordfish is highly prized in the culinary world for its firm, meaty texture and mild, slightly sweet flavor. It is often featured in a variety of dishes, such as grilling, broiling, baking, or pan-frying.
  • Versatile Cooking: Swordfish steaks are a popular choice, and they are often seasoned and cooked with various marinades and sauces.

Commercial Fishing:

  • Economic Importance: Swordfish are commercially valuable and are targeted by commercial fishing operations worldwide. They are caught using longlines, harpoons, and other fishing methods.
  • Sustainability Concerns: Sustainable fishing practices are crucial for maintaining swordfish populations, as overfishing has been a concern in some regions.


  • Size and Catch Limits: Many countries and international organizations have established regulations to manage swordfish fisheries. These regulations may include size limits, catch quotas, and measures to protect juvenile swordfish.

What is Marlin?

A marlin is a large, predatory fish belonging to the family Istiophoridae. Marlin are known for their remarkable size, speed, and distinctive elongated bills or rostrums. These fish are popular targets for sport fishing due to their strength and agility.

Physical Characteristics

  • Size: Marlins are among the largest bony fish in the ocean. Depending on the species, they can grow from 4 to 14 feet (1.2 to 4.3 meters) in length and can weigh several hundred pounds.
  • Elongated Bill: One of the most distinctive features of marlin is their long, pointed bill, which extends from the front of their upper jaw. This bill is called a rostrum and is used for hunting prey.

Species and Distribution

  • Types of Marlins: There are several species of marlin, with the most well-known being the blue marlin (Makaira nigricans), black marlin (Istiompax indica), and striped marlin (Kajikia audax).
  • Global Range: Marlins are found in warm and temperate waters of the Atlantic, Indian, and Pacific Oceans. They prefer offshore environments, often in deep waters.

Diet and Feeding Habits

  • Carnivorous Predators: Marlins are carnivorous and feed on a diet of fish, squid, and other marine organisms.
  • Hunting Technique: They are known for their speed and agility when hunting prey. Marlin use their rostrum to slash at schools of fish, stunning or impaling their prey before consuming it.


  • Pelagic Lifestyle: Marlins are pelagic fish, meaning they primarily inhabit the open ocean rather than coastal areas.
    Migrations: They are known to undertake long migrations, often following warm ocean currents.

Recreation and Sport Fishing:

  • Popular Sport Fish: Marlins are highly prized by sport fishermen for their size and challenging fights. Anglers from around the world seek to catch marlin for sport.
  • Catch and Release: Many sport fishing organizations promote catch-and-release practices to conserve marlin populations and support sustainable fishing.

Commercial Fishing:

  • Commercial Value: Marlins are also commercially valuable and are caught for their meat and other products. However, overfishing has raised conservation concerns, leading to regulations in some regions.

Conservation Status:

  • Sustainable Practices: To protect marlin populations, many countries and international organizations have established regulations and quotas to manage marlin fisheries.
  • Conservation Efforts: Efforts are underway to study marlin populations, promote sustainable fishing practices, and minimize bycatch (the accidental capture of non-target species).

Main Difference between Swordfish and Marlin

  1. Swordfish have rounded bodies while marlins have long bodies.
  2. Swordfish have visible pectoral fins while marlins do not have visible pectoral fins.
  3. Swordfish have dorsal fins that look like sharks, they extend far up and look like a feather while marlins have a single dorsal fin that connects along the back of the fish to a soft-looking ridge.
  4. Swordfish have a high content of fatty acids hence have high flavor while marlins have a mild flavor.
  5. Swordfish have long and flat snouts while marlins have round and smooth snouts.

Similarities between Swordfish and Marlin

  1. They both belong to the billfish family.
  2. Both have pink flesh.
  3. They both live in Atlantic, Indian, and Pacific Ocean waters.
  4. They are both large marine fish.

In Conclusion

In conclusion, swordfish and marlin are two distinct but closely related species of large, predatory fish, known for their size, strength, and distinctive features, including their elongated bills. While they share some similarities, such as their carnivorous diets and popularity in sport fishing, they also have several notable differences:


  • Swordfish are characterized by their impressive size, often reaching lengths of 6 to 11 feet or more.
  • They have a prominent, elongated bill that resembles a sword, which they use for hunting.
  • Swordfish are typically found in both warm and temperate waters of the Atlantic, Indian, and Pacific Oceans.
  • They are known for their firm, meaty flesh, making them a prized catch in culinary traditions around the world.
  • Swordfish do not have the distinct vertical stripes seen on marlin.


  • Marlins come in several species, including blue marlin, black marlin, and striped marlin, and can vary in size, with some exceeding 14 feet in length.
  • Marlin are recognized by their long, pointed bills or rostrums, which they use for hunting prey.
  • They inhabit warm and temperate offshore waters of the Atlantic, Indian, and Pacific Oceans.
  • Marlins are highly sought after by sport fishermen due to their size and challenging fights during capture.
  • Some marlin species, like the blue marlin, feature distinctive vertical stripes along their body, which distinguishes them from swordfish.

These differences in size, bill shape, appearance, and behavior make swordfish and marlin unique in their own right. While they both hold significant ecological and economic importance, particularly in the world of sport fishing, their distinct characteristics and habitats set them apart as individual species with their own contributions to marine ecosystems and culinary traditions.

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