The Worlds Fastest Fish - The Marine Sailfish

The world's fastest fish recorded, is the marine Sailfish. There are two species of Sailfish belonging in the genus Istiophorus: the Atlantic sailfish (Istiophorus albicans) and the Indo-Pacific sailfish (Istiophorus platypterus). 

Both species of sailfish grow very quickly, reaching a size of between 1.2 – 1.5m in a single year! Generally, an adult Sailfish does not grow to more than 3 metres in length and normally weighs somewhere in the region of 90kg. They feed on the water's surface or at mid-depths, eating smaller pelagic foraging fish and squid. So fast are these fish, that individuals have been clocked at speeds of up to an incredible 110 kilometres per hour (68 mph), which is the highest speed reliably reported for any water organism! To put that into perspective, they can swim the 100m Olympic in 4.8 seconds (in contrast, America's Nathan Adrian won gold at last year's 2012 London Olympics in the men's 100m freestyle, in a time of 47.52 seconds).

Sailfish are highly prized game fish and are widely found living in warmer sections of all the oceans of the world. They possess a startling array of colours, from subdued browns and greys to vibrant purples and even silver. Also, their body colours are often highlighted by stripes of iridescent blue and silver dots. Their common name comes from having a characteristic erectile dorsal fin (known as a sail), which often stretches the entire length of the back. Another notable characteristic of this majestic fish is the elongated bill, resembling that of the Swordfish and other Marlin fish, and for this reason, they are also commonly known as 'Billfish'.

Their impressive dorsal sail fin, which is normally kept folded down and to the side when swimming, also has a very useful purpose. They will often raise this fin when the fish feels threatened or excited, therefore making the fish appear much larger than it actually is. They are known to deploy this tactic during feeding, when a group of sailfish use their sails to 'herd' a school of fish or squid and create a 'bait ball'. Additionally, they can rapidly alter their body colour to a light blue (with yellowish stripes) when excited, confusing the prey and making capture easier, while signalling the fish's intentions to other fellow sailfish. A truly impressive animal!