Filefish are sometimes called leatherjackets, a somewhat inappropriate name, as it was their rough skin which inspired their common name. Dried filefish skin was once used to finish wooden items.
Filefish are found in the tropical and subtropical waters of the Atlantic, Pacific and Indian Oceans. They are closely related to triggerfish, boxfish and pufferfish but unlike these close relatives have flat, almost 2-dimensional bodies with small pectoral fins and truncated, fan-shaped tail fins making them very poor swimmers. However, this odd, flattened shape is also their main advantage – showing their flank to a predator makes them appear much larger than they are while their side-on, narrow profile allows them to almost disappear. The various filefish species also use their vibrant body patterns, colours and decoration to merge with their background.
These small fish are found in a wide variety of marine environments from coral reefs and lagoons to seagrass beds and even in the mouths of river estuaries. The largest filefish species is the scrawled filefish, which is seen on coral reefs and can grow up to 110 centimetres (43 in) in length.
Filefish spawn on sites that are close to the seabed. The male prepares the site then, depending on the species, will either guard it alone, or with the female, until the young filefish hatch and take off into open water.