Oreosomatidae, the oreos, are a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of marine

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

. Most species are found in the Southern Hemisphere, inhabiting

continental slope A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...

s down to about deep. Most of then are 43 cm at most, with the largest species reaching a length of 60 cm. Though they are small, they often have incredibly elongated lifespans, probable result of living in the deep sea (a trait shared with other unrelated fishes like the

orange roughy The orange roughy (''Hoplostethus atlanticus''), also known as the red roughy, slimehead and deep sea perch, is a relatively large deep-sea fish belonging to the slimehead family (Trachichthyidae). The UK Marine Conservation Society has categori ...

) with the warty oreo being able to live up to 210 years, which puts it at one of the longest living vertebrates on Earth. They borrow their name from the Greek ''oreos (''mountain) and ''somas'' (backs) for the shape of their backs. They are very flattened vertically-laterally, with 5 to 8 rays in their

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

, and 2 to 4 in the anal fin, and only 1 spine in the pelvic fins. The upper part of the mouth is protractile, allowing them to snatch up little fishes, copepods, amphypods, shrimp, krill, and small cephalopods, their main diet.

References

Ray-finned fish families Zeiformes {{Zeiformes-stub