Are sailfish truly the ocean's fastest sprinters, or is that a marine myth?

Nature · Published 3 October 2026 Swipe more like this →

In short: Long celebrated as the fastest creatures in the sea, sailfish were once thought to hit speeds of 80 mph. Recent research suggests a more modest reality, revealing that these billfish rely on sophisticated group hunting tactics and behavioral specializations rather than raw, record-breaking velocity to secure their next meal.

For decades, the sailfish held a legendary reputation for blistering speed, with older estimates claiming they could reach 35 meters per second, or 125 kilometers per hour. However, scientific consensus has shifted following studies published in 2015 and 2016. These investigations indicate that sailfish do not actually exceed speeds of 10 to 15 meters per second. During active predator-prey interactions, they rarely surpass 10 meters per second, suggesting that their reputation for extreme velocity may be an exaggeration.

Beyond their speed, sailfish are masters of tactical hunting. They possess a signature dorsal fin—the sail—which they keep folded while swimming but raise during attacks. This fin helps stabilize the fish, reducing head oscillations and allowing them to approach prey schools undetected. Once close, they use their elongated bills to tap or slash at schooling fish like sardines. This behavior often injures prey, slowing them down and making them easier targets. Because only about 24% of these attacks result in capture, sailfish often benefit from the injuries inflicted by their peers.

This cooperative behavior, termed proto-cooperation, does not require complex spatial coordination. Instead, it allows sailfish to hunt in groups of up to 70 individuals. Interestingly, individual sailfish often develop a side preference for hitting prey—either left or right—which correlates with their hunting success. While this specialization could theoretically make them predictable to prey, living in groups mitigates this risk. By mixing individuals with different side preferences, the group ensures that prey cannot easily anticipate the direction of the next strike, demonstrating a novel evolutionary advantage to group hunting.

Taxonomically, the status of the sailfish remains a subject of debate. While some sources identify two species, most modern authorities recognize only a single species, Istiophorus platypterus. Regardless of classification, these fish grow rapidly, reaching up to 1.5 meters in their first year. They remain vital to their ecosystems, though their presence is closely tied to habitat health; in areas like the Persian Gulf, the loss of coral reefs has been linked to the local disappearance of the species.

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