Fun Billfish Facts For Kids | Kidadl


Fun Billfish Facts For Kids

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If you like fish, then here we have a ton of information about the 12 different species of sailfish, swordfish, spearfish, and marlin, or otherwise known as billfish. These marine species can be found in the Atlantic, Pacific, and Indian oceans. They are migratory animals. They are seen migrating through many places and seasons such as the white marlin migrates from May to October. The conservation of both Atlantic blue marlin and white marlin needs to be put in place as their population is threatened. They are considered great game fish but as billfish are large, anglers need to have experience in fishery techniques to catch them. The blue marlin is one of the largest fish in the oceans and sailfish are one of the fastest in the oceans. They are eaten in many parts of the world but they are not that great in terms of flavor. They have distinctive bills in the front that are either sword or spear-shaped.

Read on for additional facts and information on billfish, and if you like this article, then check out our other articles on drum fish and sawfish.

Fun Billfish Facts For Kids

What do they prey on?

Bony fish, schools of smaller fish, crustaceans, and squid

What do they eat?


Average litter size?

Several million

How much do they weigh?

1800 lb (820 kg)

How long are they?

10-16 ft (3-5 m)

How tall are they?


What do they look like?

Blue, yellow, and silver

Skin Type


What were their main threats?


What is their conservation status?

Least Concern: Indo-Pacific sailfish Data Deficient: Roundscale spearfish Vulnerable: Blue marlin Near Threatened: Striped marlin

Where you'll find them?

Tropical And Temperate Waters


Indian, Pacific




Xiphias and Istiompax




Xiphiidae and Istiophoridae

Billfish Interesting Facts

What type of animal is a billfish?

Billfish is a kind of fish and there are 12 species of billfish.

What class of animal does a billfish belong to?

Billfish belongs to the class Actinopterygii of animals.

How many billfish are there in the world?

There are many different species of billfish and while the population of some among them is at an abundance, the population of some species is still unknown to us. The total population of billfish is not known.

Where does a billfish live?

All the different species of this fish live in the oceans around the world such as the Indian, Pacific, and Atlantic oceans. They are migrating fish, so they move around the world in accordance with the season and the temperature of the ocean water. There has not been much research done on this, so the information on their exact movement pattern is not known.

What is a billfish's habitat?

Billfish live in all oceans around the world, but they prefer to stay in a tropical and temperate environment. They stay around the continental shelves and offshore where there is the most amount of fish to prey on. They migrate according to the temperature of the water.

Who do billfish live with?

Billfish are solitary animals. They usually live alone and forage on their own.

How long does a billfish live?

Billfish can live up to 25 years in the ocean.

How do they reproduce?

The breeding season for this fish varies according to the different species, such as marlin fish breed during late fall and summer, and sailfish breed around April. The fertilization of billfish happens externally. A female billfish release the eggs in the water and a male billfish releases the sperm over them for the fertilization process to happen. Females may release millions of eggs at a time.

What is their conservation status?

According to the International Union for Conservation of Nature, the conservation status of many species among the billfish are listed as Least Concern such as the Indo-Pacific sailfish (Istiophorus platypterus) and the longbill spearfish (Tetrapturus pfluegeri). The conservation status of many species, like the roundscale spearfish (Tetrapturus georgii), or the shortbill spearfish (Tetrapturus angustirostris) are listed as Data Deficient. Also, the conservation status of the Atlantic blue marlin (Makaira nigricans), and white marlin (Kajikia albida) are listed as Vulnerable and the striped marlin (Kajikia audax) is listed as Near Threatened.

Billfish Fun Facts

What do billfish look like?

The physical features of billfish differ in the cases of spearfish, sailfish, marlin, and swordfish. They all have a long body and on the front, they have a long spear or sword-shaped bill which they use to prey on small fish. A swordfish has the longest bills and the others have rounded ones. They have fins on their abdomen that help them steer corners smoothly in the water, and their dorsal fin helps them gain speed when swimming.

Billfish, like swordfish, are natural predatory marine animals.

Why are billfish not kosher?

For a fish to be considered kosher, they need to have scales and fins. While all billfish have fins, some of them have scales, while others don't like swordfish. Even with swordfish, they only have scales when they are young and so, they are considered non-kosher.

How do they communicate?

Billfish communicate by sound, vibration, and visually. They find their prey visually and through vibrations in the water. They also get a good sense of their surroundings by the vibrations they feel around them.

How big is a billfish?

The size of billfish varies according to the species but on average, they grow up to 10-16 ft (3-5 m) long. They are much smaller than great white sharks, who are about 23 ft (7 m) in length.

How fast can a billfish swim?

Billfish can swim pretty fast. They can be seen swimming at a speed of more than 45 mph (72 kph). Sailfish among all billfish are considered to be the fastest and can swim at a maximum speed of approximately 70 mph (110 kph).

How much does a billfish weigh?

Billfish are large fish. An adult billfish can weigh up to a mighty 1800 lb (820 kg).

What are their male and female names of the species?

There are no specific names for males or females of this species.

What would you call a baby billfish?

When the eggs of any fish hatch, they are called 'larvae', but young juvenile fish are called 'fry'.

What do they eat?

Billfish have large bills by which they usually prey on schools of fish and their bills can be so sharp that they can cut their prey in two just by using their bills. Billfish prey on mackerel, squid, tuna, crustaceans, and large bony fishes. The fry is known to eat zooplankton.

Are they eaten by humans?

Billfish, like sailfish, are not that great in terms of taste, but many people do eat them. Sailfish, spearfish, and swordfish are eaten in many places of the world, but consuming marlin in large amounts can be harmful to us.

How closely related are billfish and tuna?

Billfish and tuna have a few similarities such as both fish have the ability to keep the temperature of their body warmer than their surrounding waters. Also, they both migrate across far distances. Both of these types of fish can withdraw their dorsal fins in their body, so there's less friction when they are swimming and as a result, they can swim forward at a faster speed.

Did you know...

Some conservation action has been taken for the billfish species that are somewhat threatened, like the Atlantic blue marlin, white marlin, or striped marlin. Long-lining has been banned in many places and whether through bycatch or some other technique of fishery, fishing of billfish has been banned in many places. Too much fishing of the Atlantic Blue marlin was happening at one time. Hence, fishing of the particular species became illegal.

Ernest Hemingway used to go fishing for white marlin and Atlantic blue marlin in Florida Keys, Cuba, and the Bahamas.

Are billfish territorial?

Swordfish can show territorial behavior. They are known to be somewhat aggressive when protecting their territory. Sailfish are not known to be territorial, and in the case of spearfish and marlin fishes, the information on whether they are territorial or not is not known.

What are some other names for billfish?

Billfish can be divided into four different kinds of fish which are sailfish, swordfish, spearfish, and marlin. They don't have any other nicknames.

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 cuttlefish, or clownfish.

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

Written By
Moumita Dutta

Moumita is a multilingual content writer and editor. She has a PostGraduate Diploma in sports management, which enhanced her sports journalism skills, as well as a degree in journalism and mass communication. She's good at writing about sports and sporting heroes. Moumita has worked with many soccer teams and produced match reports, and sports is her primary passion.

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