Distribution:
Atlantic, Indian and Pacific oceans.
Habitat:
Most species occur in deeper water, at depths between 100 and 1500 m.
Remarks:
Also known as slimeheads, roughies have a network of mucous-secreting pores on their large, blunt heads. These fishes have large eyes and mouths, and are often very brightly colored.
The family name "Trachyichthyidae" comes from the Greek trachy, meaning "rough" and ichthys, meaning "fish," although scales are variable between species, ranging from thick and spiny to thin and cycloid.
Roughies have a distinct spine at angle of preopercle and a posteriorly pointing spine on posttemporal bone. The area between the pelvic fin and the anus houses a ridge of bony scutes. They are deep-bodied fishes and can achieve a maximum length of 55 cm.
Roughies feed primarily on zooplankton, such as larval fishes, amphipods, euphausids, shrimps and other crustaceans. They have a low activity level, often aggregating over undersea canyons or seamounts. Some species are luminescent.
Some species, notably the orange roughy, are important commercial foodfishes, but, due to overfishing and slow reproductive rate, their populations are easily depleted.
This family comprises seven genera and about 39 species.
References:
Nelson 2006