The Sailfish is the Fastest Fish in the World

The sailfish’s mesmerizing dorsal fin isn’t the only thing it’s famous for

When it comes to a fish’s ability to be simultaneously majestic and athletic, none can quite compare to billfish. And while all the marlins, spearfish and swordfish on our blue planet are impressive in their own right, I’ve always thought there to be something truly mesmerizing about one billfish in particular: the sailfish (Istiophorus).

Weighing up to about 200 pounds and measuring anywhere from six to 11 feet in length, these striking pelagic creatures are, of course, called “sailfish” for a reason. They credit their name to their massive sail-like dorsal fin, which bears quite the resemblance to (you guessed it) the sail of a ship. Often stretching the entire length of the animal’s body, the sail of a sailfish is truly an incredible sight to behold—but it’s also not all for show! Today, I’m here to share some sensational facts about these brilliant billfish, from their famed “sails” to their impressive speed and everything in between.

How to recognize a sailfish

It probably comes as no surprise that these unique-looking swimmers have quite a few distinguishing features. First, there’s that massive, jaw-dropping sail (their dorsal fin) that graces the back of their bodies. These sails are sometimes taller than the rest of the fish’s body! While this trademark sail serves a number of purposes (we’ll dive into that in a moment), it’s important to note that these fish don’t always swim with their sails extended as they’re often depicted in photos. Keeping the sail folded down helps the fish streamline its physique in order to swim faster and more efficiently, so this famous feature isn’t always quite so obvious to an observer.

Apart from their dorsal fins, sailfish have long, pronounced bills that form as a result of their upper jaws protruding heavily beyond their lower jaws (this, of course, is what makes them members of the billfish club!). One way to differentiate between sailfish and other billfish is by paying close attention to the sides of the fish’s body. Sailfish have up to 20 vertical stripes of faint dots on their sides which are typically bluish in color.

Sailfish illustration photo

Where they live

You can find most sailfish in tropical and temperate waters around the world. These fish are migratory, moving closer to the equator when the waters are cooler in autumn and returning to higher latitudes as the summer months near. Sailfish belong to a largely pelagic species, meaning that they live the vast majority of their lives in the open ocean, usually hanging out closer to the water’s surface. They’re not afraid to dive deep when it comes to hunting for food, however. In fact, these determined predators have been known to visit depths of more than 1,000 feet below the surface in search of their next meal.

When it comes to hunting prey, sailfish are the track stars of the ocean

Sailfish have quite a few favorite prey, including smaller fish such as sardines, anchovies and occasionally mackerel. Sailfish in the Atlantic Ocean even eat cephalopods, too (think smaller octopus or squid). Since they spend most of their time gallivanting through the waters of the open ocean, sailfish get plenty of practice when it comes to tapping into top-notch speeds to hunt. They are often spotted working in pairs or small groups and using their sails to herd their prey around. And, when chasing after a school of fish (aka a combo meal), these fierce swimmers never fear a challenge. They’re known to fold their fins back completely, their bodies resembling a torpedo as they dash toward their targets at speeds of up to 68 miles per hour. Because of this, sailfish are widely regarded as the fastest animals to call our ocean home.

Sailfish in Paradise: Their valiant fight for love

Another area in which sailfish are fearless? Romance, of course! When mating season arrives, females will extend their brilliant dorsal fins to show off to curious males nearby. These males are known to be quite aggressive in their pursuit of a mate, often competing with other suitors in an intense race as they chase after the female to see who is strong and fast enough to make it to her first. Once a male and female sailfish are finally paired, they engage in what’s called broadcast spawning, where males and females pair up and release their eggs and sperm into the water beside each other. Females can release millions of eggs at once to increase the chance of fertilization. One more quick fact:when it comes to baby sailfish, these fish start out very tiny! Recently-hatched larvae usually measure only a couple millimeters in length, with most of their growth happening within the first year of their lives (that’s a lot of growth in a short span of time).

Modern threats to our ocean’s sailfish

As glorious as our ocean’s sailfish are, there are man-made risks that still pose a threat to their survival. Because of their beauty and speed and the challenge they pose to recreational fishers, sailfish are often caught and released by sport anglers, but they’re not permitted to be fished commercially in U.S. waters. Even though they’re rarely sought after for anything but catch-and-release fishing, there’s still a quiet but prominent danger that lurks beneath the surface for these animals: ghost gear.

“Ghost gear” refers to any fishing gear that is abandoned, lost or discarded into marine environments, including items such as fishing nets, long lines, stationary traps and any other human-made device used to catch marine animals. Because fishing gear is designed to capture marine organisms, it can continue to do so long after the gear is lost or discarded into the sea. When these pieces of gear continue to “fish” even after being lost or discarded, it is called “ghost fishing.” Adult sailfish don’t have many natural predators in the open ocean, but the risk of encountering ghost gear for sailfish and countless other species is ever-present in the waters where they live.

That’s why Ocean Conservancy’s Global Ghost Gear Initiative (GGGI) is working every day on the frontlines of developing and supporting innovative solutions to combat ghost fishing, working with partners around the world both to remove ghost gear currently lost at sea and prevent more from being discarded in the future.

Dive in today and learn how you can help protect sailfish by supporting the GGGI and the work this program is doing to combat this dangerous form of marine debris here.

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