What is a Filefish?

Filefish, also called leatherjackets, foolfish, and shingles, is a fish that spans more than 25 genera. They are normally found in shallow tropical or sub-tropical waters around the world, swimming alone, in pairs, or small groups, depending on the species. Their bodies usually have an odd shape and appear much larger when viewed from the side. The common name filefish is derived from the rough, papery skin that covers their body, which was supposedly once used to sand wood. In some countries, filefish are used to make a roasted jerky snack.

The appearance and size of these fish can vary significantly depending on the species. They typically have intricate patterns made of spots, blotches, or stripes. These patterns can be almost any color, ranging from black and white zebra-like stripes to bright blue with yellow and orange spots. In general, the color of some types of fish reflects their habitat in the sea; for example, filefish that live near reefs might have scales that mimic the color and texture of that reef. The largest known filefish species is Aluterus scriptus, which is about 3.5 feet (1 m) long, though other species tend to be half that size or smaller.

Filefish are normally born on the ocean floor and wander into the open sea at a young age, after being guarded by their parent fish. Some types of these fish, however, drop eggs onto the open ocean and do not guard them. In the open sea, the young fish are frequently eaten by tuna and dolphinfish, the latter of the two being unrelated to dolphins despite their name. More specifically, filefish are found in all oceans except the Arctic Ocean. These fish can also be found in aquariums as pets or exhibits.

The fish are often kept as pets and, depending on the species, may require an aquarium that can hold at least 50 gallons of water. Filefish are generally considered to be very congenial and non-aggressive when living in a suitable aquarium environment, but certain species may act aggressively toward smaller fish or those that are closely related to them. In captivity, it is generally considered important to feed these fish at least a few times a day. It is typically advisable to feed them a variety of meaty seafood, such as shrimp and scallops, though some will eat marine algae. An important aspect of making an aquarium environment healthy for many of these fish involves providing them with sufficient natural cover to shelter in.