Fun Black Marlin Facts For Kids

Christian Mba
Oct 27, 2022 By Christian Mba
Originally Published on Aug 05, 2021
Edited by Isobel Murphy
Fact-checked by Spandana Kantam
Black marlin is one among the 10 fish species of Istiophordae
Age: 3-18
Read time: 6.6 Min

The black marlin (Istiompax indica) has its name on the list of some of the speediest swimmers on the earth. They are found in the tropical and subtropical waters of the Indian Ocean and the Pacific Ocean. To watch a giant black marlin leaping out of deep-sea blue waters is a truly spectacular and unforgettable experience. Famous as a game fish, the black marlin is highly prized among sports fishermen too.

With black dorsal and a silvery-white underneath, they are cousins of the swordfish and sailfish and, like other billfishes, have long bills. Female black marlins are larger than the males. These black marlins are commercially fished for their expensive meat which is a favorite dish of many who love eating fish. These beautiful bony fish are abundant in sea waters, but with the increase in the fishing of marlins, this species will soon become a rarity.

If you like this article and find it informative, then you can read about the swai fish and anchovies too!

Black Marlin Interesting Facts

What type of animal is a black marlin?

The black marlin, scientifically known as Istiompax indica, is one of the 10 fish species from the family Istiophordae. It is closely related to the swordfish and sailfish in appearance. A shorter bill, lower dorsal fin, and rigid pectoral fins are the distinguishing features of a black marlin. Also, the black marlin does not have retractable fins.

What class of animal does a black marlin belong to?

Black marlins belong to the class Actinopterygii. The scientific name of a black marlin is Istiompax indica. Bony or horny spined fins and non-fleshy fins are other distinguishing features. The black marlin can not press flat their rigid pectoral fins (which weigh around 150 lb (68 kg)) to their sides.

How many black marlins are there in the world?

With insufficient data available on the population of black marlins, it is difficult to know the exact numbers. But these marlins are widely found in the tropical and sub-tropical waters of Indo-Pacific ocean region and sometimes in temperate waters.

Where do black marlins live?

The black marlin lives in the oceans. They are found in the tropical and subtropical waters of the Pacific Ocean, Indian Ocean, and the Atlantic Ocean. Sometimes they also enter temperate waters.

What is a black marlin's habitat?

The black marlin lives above the thermocline, in shallow waters most of the time. They prefer to be close to the land and coral reefs. However, they can swim to a depth of almost half a mile (800 m). The black marlin is a migratory species and is occasionally found in the Atlantic Ocean but prefers breeding in the Indo-Pacific waters.

Who do black marlins live with?

The black marlin prefers to swim alone but occasionally can be seen in pairs. Juvenile fish school together for a certain period of time, but adults mostly keep to themselves except during the breeding season. During the breeding season, comparatively smaller males follow larger females to the spawning areas.

How long does a black marlin live?

Female black marlins live up to the age of 11 years, whereas male black marlins can live for about five years.

How do they reproduce?

Black marlins reproduce by external spawning. The females release around 40 million eggs into the water in batches during the breeding season. And the males release their sperm to fertilize these eggs. The tiny larvae fish hatch in two days and easily fall prey to predators without any parental care. They school together for a year or so, but only a few of these manage to reach adulthood. Predators eat the eggs and larvae, hence the release of such a large number of eggs by females.

What is their conservation status?

Data on the population of black marlin fish is insufficient. Hence, its status is Not Evaluated.

Black Marlin Fun Facts

What do black marlins look like?

They look like swordfish and sailfish and have a resemblance with other species of marlin fish. They have rigid pectoral fins, unlike other marlin fish. The dorsal fin of the black marlin is black, and the belly or the lower half is silvery-white in color.

The black marlins hold a resemblance to swordfish and sailfish.

How cute are they?

With a black dorsal and a white lower body, black marlins are cute animals to watch when they leap out of the ocean.

How do they communicate?

Marlins supposedly communicate by sending mind waves to each other. Not much information is available on this and research is ongoing.

How big is a black marlin?

Black marlin's size varies between the two genders. The black marlin can grow to a length of 15.3 ft (4.65 m). They grow really fast, and a small juvenile fish reaches around 33 lb (15 kg) by the end of their first year. Comparatively, they are smaller than tiger sharks.

How fast can a black marlin swim?

The black marlin is said to be faster than a cheetah. The black marlin can swim between 20-50 mph (32.2-80.5 kph), and a few records project that a large one can go up to 80 mph (128.8 kph).

How much does a black marlin weigh?

Black marlin can reach weights of up to 1653 lb (750 kg). Females are larger than males and are almost double their size. A black marlin that weighs over 1,000 lb (453.6 kg) is known as a 'grander'.

What are their male and female names of the species?

Both the male and female species of black marlin do not have any specific names allotted to them individually.

What would you call a baby black marlin?

A baby black marlin is not given any special name and is just referred to as a baby black marlin.

What do they eat?

The black marlin prefers small tuna fish but also feeds on cuttlefish, squid, mackerel, and octopuses. They kill their prey by slashing their body with their sharp bills.

Are they dangerous?

The black marlin is one of the top predators of the seas. So yes, they are dangerous and can be aggressive, especially with anglers.

Would they make a good pet?

No, they are one of the largest and fastest marine animals and are best left in ocean waters. Despite this, they are a favorite among recreational anglers as game fish.

Did you know...

A black marlin that turns blue is a common phenomenon observed in this species. The colors presented by the marlin are one of their most spectacular features. Under a microscope, a marlin has tiny crystal-like structures punctuated by dark cells known as melanophores under the mucous layer. When agitated, the melanophores of a black marlin become contracted to make the tiny crystals reflect light. The light reflected off the marlin is dark blue because of the diffraction pattern of the crystals.

The black marlin vs. blue marlin comparison is really interesting! The blue marlin is endemic to the Atlantic Ocean and is closely related to the black marlin. A blue marlin prefers the open sea away from land, unlike the black marlin. Both species have many similarities with only very few differences in their body color and shape of the fins.

The black marlin is worth about $31,000 per lb. Very expensive, right?

One of the fastest fish in the world

At a record speed of 80 mph (128.8 kph), the black marlin is said to be one of the fastest fish on earth. There is a disagreement among experts as to the fastest between sailfish and black marlin, but undoubtedly black marlins are known for their speed.

The extremely streamlined body of a black marlin with its fusiform shape and rigid semi-lunate tail powering it through the water makes a black marlin so fast. The fusiform shape means that the fish is wider in the middle part of the body and tapered at the ends. Its semi-lunate (half moon-like) tail is the reason that it can take those wonderful spinning leaps out of the water.

Black marlin and fishing

Black marlin is among the most sought-after fish and are a favorite among sports fishermen. Their popularity as a game fish can be seen by world-class tournaments that take place surrounding the fish. The International Game Fish Association currently holds the world record for the biggest black marlin catch at 1,560 lb (707.6 kg). This was caught by Alfred Glassell Jr in 1953, while fishing off Cabo Blanco, Peru.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other fish including codfish, or fluke fish.

You can even occupy yourself at home by drawing one on our black marlin coloring pages.

Black Marlin Facts

What Did They Prey On?

Tuna, mackerel, squid, crustaceans, and octopus

What Type of Animal were they?

They are omnivores

Average Litter Size?

Up to 40 million eggs

How Much Did They Weigh?

Up to 1653 lb (750 kg)

What habitat Do they Live In?


Where Do They Live?

Indian and Pacific oceans

How Long Were They?

Up to 183.6 in (4.6 m)

How Tall Were They?

We're not sure how tall this fish is. If you know, please let us know at







Scientific Name

Istiompax indica

What Do They Look Like?

They are dark blue-black and white in color

Skin Type


What Are Their Main Threats?


What is their Conservation Status?

Not Evaluated
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Written by Christian Mba

Bachelor of Science specializing in Computer Science

Christian Mba picture

Christian MbaBachelor of Science specializing in Computer Science

Christian Mba is an experienced blogger and content writer with over a decade of experience. He holds a Bachelor of Science degree in Computer Science from Nigeria and has a keen interest in Python programming. Along with his writing and blogging expertise, he is also an SEO specialist with more than six years of experience. Chris, as he is commonly known, has a passion for music and enjoys playing the piano.

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