Grenadiers (fish)

Grenadiers or rattails are generally large, brown to black gadiform marine fish of the family Macrouridae, the largest family of the suborder Macrouroidei. Found at great depths from the Arctic to Antarctic, members of this family are amongst the most abundant of the deep-sea fish.

The macrourids form a large and diverse family with 28 extant genera recognized (well over half of the total species are contained in just three genera, Coelorinchus, Coryphaenoides, and Nezumia). They range in length from about 10 cm (3.9 in) in Hymenogadus gracilis to 2.1 m (6.9 ft) in Albatrossia pectoralis. Several attempts have been made to establish a commercial fishery for the most common larger species, such as the giant grenadier, but the fish is considered unpalatable, and attempts thus far have proven unsuccessful. The family as a whole may represent up to 15% of the deep-sea fish population.

Rattails, characterized by large heads with large mouths and eyes, have slender bodies that taper very much to very thin caudal peduncles or tails (except for one species without a caudal fin): this rat-like tail explains the common name "rattail" and the name of the family and the surname are derived from the Greek makros meaning "big" and oura meaning "tail". The first dorsal flat is small, tall and pointed (and may have rays modified into spines); The second dorsal fin runs along the rest of the back and connects to the tail and the large anal fin. The scales are small.

As with many deep-living fish, the lateral line system in grenadiers is well-developed; it is further aided by numerous chemoreceptors located on the head and lips and chemosensory barbels underneath the chin.