Swordfish vs Marlin: Learn the Difference

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.


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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.

Key Takeaways

  1. Swordfish and Marlin are two types of large, predatory fish found in oceans worldwide.
  2. Swordfish have a long, flat bill and are known for their impressive speed and agility, while Marlin has a more pointed bill and is often more prominent.
  3. While fishermen prize both fish for their sport and culinary value, they have distinct physical and behavioral differences that set them apart.

Difference Between Swordfish and Marlin

The 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.

Swordfish vs Marlin

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Comparison Table for Swordfish vs Marlin

Parameters of ComparisonSwordfishMarlin
Dorsal Fin ShapeThe dorsal fin of a swordfish resembles a shark’s tail. Its appearance is similar to the shape of a feather.The dorsal fin of a marlin connects to the back of the fish by sloping gently into a soft ridge.
Body StructureA swordfish has an elongated, but round body.A marlin has a long cylindrical body.
Pectoral FinsPectoral fins are conspicuous.Miniscule pectoral fins that are almost invisible.
Shape of SnoutThe snout of a swordfish is long and flat.The snout of a marlin is long and round.
WeightThe average weight of a swordfish is lower than that of a marlin.The average weight of a marlin is higher than that of a swordfish.
LengthSwordfishes are longer than marlins. The average length of a swordfish ranges from 7-15 feet.Marlins are smaller than swordfishes. Marlins can grow up to 14 feet.
SpeedSwordfish are slower swimmers than marlins. The average speed of a swordfish is 97 km/h.Marlins are faster swimmers. The average speed of a marlin is 132 km/h.
TasteThe flesh of a swordfish has a strong flavor.The flesh of a marlin has a milder flavor.

What is a Swordfish?

Swordfishes are widely renowned long, flat snouted members of the billfish family. They are commonly found in warm marine waters.

The distinctive dorsal fin of a swordfish separates it from other descendants of the same familial order. The dorsal fin of a swordfish bears a close resemblance to a shark’s tail.

They often tend to be mistakenly perceived as sharks. The fin’s structure is also commonly compared to that of a feather.

The body of a swordfish is elongated but spherical. The length of an average swordfish ranges from 7-15 feet.

The especially elongated snout can make up for almost one-third of a swordfish’s body length. Traveling at a speed of 97 km/h, they use their long snouts to injure smaller fish and other prey.

Unlike marlins, the color of a swordfish’s body can range from dark brown to black.

Swordfish meat is used to prepare fish fillets. The strong flavorful aroma of the fish makes it a perfect fit for most winter soup recipes.


What is a Marlin?

The marlin is a deep-sea fish that is commercially marketed across the world for its distinctive taste and flavor. It also belongs to the varied line of billfishes.

Marlins typically thrive in warm tropical and temperate waters. They are natives of the Indian, Atlantic, and Pacific oceans.

Marlins have a large, cylindrical body with a long but rounded snout. The dorsal fin of a marlin is similar to a sailfish.

Marlins use their snout as an effective weapon for hunting.

Their diet comprises of smaller fish, squids, and planktons. The snout helps the marlin navigate through the shoals of smaller fish, inflicting injuries on the prey.

On average, marlins grow to a length of 14 feet and weigh up to 650 kilograms. The sub-variants of the marlin family are often categorized by the color of their scales.

The black Pacific marlin, blue marlin, and the white marlin are the most common members of the family. Their texture and taste make them popular choices for preparing Japanese-style sushi.


Main Differences Between Swordfish and Marlin

  1. The main difference between a swordfish and a marlin is the dorsal fin shape of each fish variant. The dorsal fin of a swordfish is large and resembles a shark’s tail. While a marlin’s dorsal fin connects to a soft ridge on the back of the fish. It peaks in the front and gently slopes downwards.
  2. The second seminal difference between the two in terms of the body structure of each fish. The swordfish has an extended, but spherical body, while the marlin has a long, almost tubular body structure.
  3. A swordfish has pectoral fins that extend beyond its lower body. However, a marlin can be recognized by the several minuscule pelvic fins it bears. These fins are almost invisible due to their exceptionally small size.
  4. Swordfishes generally weigh lesser than marlins. The average maximum weight of a swordfish is around 450 kilograms, while that of a marlin can be 680 kilograms.
  5. Owing to its elongated body and snout, a swordfish can be longer than a marlin. The average length of a swordfish is 7-15 feet, while a marlin can measure up to 14 feet.
  6. Another significant difference between the two is in terms of the shape of the snout of each. The snout of a swordfish is flat, while that of a marlin is round.
  7. A swordfish is comparatively slower than a marlin. The black marlin is the fastest underwater animal, traveling at a speed of 132 km/h. While the highest speed recorded for a swordfish is 97 km/h.
  8. The two billfishes also differ in terms of the taste and color of their flesh. The taste of swordfish meat is stronger. The flesh has a lighter pigmentation and is often used in the preparation of soups or as grill fillets. On the other hand, a marlin’s milder flavor is considered suitable in the preparation of Japanese-style sushi. The meat is generally fatty and denser than swordfish meat.
Difference Between Swordfish and Marlin


Swordfish and marlin are both renowned types of billfish. Both these varieties of fish are found in the warm tropical marine waters.

Both have similar hunting techniques and diets. This often confuses the general populace as they frequently fail to distinguish one from the other.

However, both have some very telling differences. The weight, length, speed, and taste of each variety are rather different when compared to the other.

The most striking difference is noted in terms of appearance. When examined closely, the appearance of a swordfish is quite different from a marlin.

A swordfish is elongated and round, with a flat long snout. A marlin, on the other hand, is tubular and cylindrical, with a round snout.

The dorsal fin of a swordfish is like a shark’s distinctive-looking tail, while a marlin has a tail that looks quite different. These differences might come in handy while selecting a suitable fish for a fancy preparation.

Nonetheless, one cannot easily distinguish between the two when they are cooked and served.

  1. https://www.sciencedirect.com/science/article/pii/S0956713504001148
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