The dorsal fin spines of the yellowfin leatherfish contain a painful venom.
There are two fish commonly known as leather jacket fish: Olgoplites saurus and a wide variety of fish in the Monacanthidae family. The former can be commonly found in the Gulf of Mexico and parts of the Atlantic. The latter is usually found near New Zealand waters.
The Olgoplites saurus is a fish of the Carangidae family and is generally found in the Gulf of Mexico and along the southern part of the Atlantic coast. From time to time it travels to colder waters and some stray animals have been sighted and captured in the extreme north of Maine. The fish prefers beach and reef waters and travels in small schools that have been seen jumping out of the water during the journey.
The fan-bellied leatherjacket fish can be identified by its diamond-shaped body and darker coloration.
Their coloration is split horizontally, with the upper half typically having a bluish tint, while the lower half is silvery. The fins of the fish are yellow. The most notable feature of the fish is the dorsal fin, which is very long and breaks off, giving the appearance of several small fins that cover the spine like the brushes of a comb. These little dots are poisonous and, if bitten by a human, can cause very painful wounds. It typically grows to about 10 inches (27 cm) long and weighs about 10 ounces (287 grams). It is sometimes caught and traded as fish, but it is not very popular as such.
Leather jacket fish of the Monacanthidae family are usually found near New Zealand waters.
The term “leatherfish” is also used to describe a wide variety of species in the fish family Monacanthidae that inhabit the waters surrounding Australia and New Zealand. The various species of leather jackets in the area are often called a reef leather jacket, a velvet leather jacket, or a soft fish leather jacket.
It can vary in size, but most weigh around 800 grams and are around 38 cm long, although some species are larger. Leatherjackets can grow up to 60 cm and weigh three pounds (1.5 kg), while reef leatherjackets can weigh around 3.5 kg.
All species share common features and lack scales. Instead, the fish has thin skin, from which the animal gets its name. All fish species also have very large dorsal fins that resemble horns. The fish generally feed on small invertebrates, sea sponges, and plankton and live at average depths between 65 and 650 feet (20 and 200 meters). Unlike the leather jacket fish of the Atlantic coast, these leather jacket fish have no venom and are almost always harmless to humans.
The various species have been known to bite and peck at the fingers of approaching divers, but these bites are not serious. It is caught commercially in New Zealand and Australia, and fish bought cheaply in markets can be prepared in a variety of ways, including blanching, steaming, grilling, and frying.