Grenadiers or rattails are generally large, brown to black gadiform marine fish of the subfamily Macrourinae, the largest subfamily of the family Macrouridae. Found at great depths from the Arctic to Antarctic, members of this subfamily are amongst the most abundant of the deep-sea fish.
Macroudidae is a family of deep sea fish, a diverse and ecologically important group, which are part of the order of cod-like fish, the Gadiformes. The species in the Macrouridae are characterised by their large heads which normally have a single barbel on the chin, projecting snouts, and slender bodies that taper to whip-like tails, without an obvious caudal fin but what there is of the caudal fin is often confluent with the posterior dorsal and anal fins. There are normally two dorsal fins, the anterior dorsal fin is quite high, the posterior quite low but is longer and takes up a greater proportion of the fish's of the back, species in the subfamily Macrouroidinae have a single dorsal fin. The long anal fin is almost as long as the second dorsal fin is nearly as long as the posterior dorsal, and sometimes it is longer. The pelvic fin is inserted in the vicinity of the thorax and normally has 5-17 fin rays but are absent in Macrouroides. The body is covered in small scales and if they have a photophore, it is usually on the midline of the abdomen just in front of the anus. The bioluminescence of these fish is produced by symbiotic bioluminescent bacteria. The structure of the skull has been used to show their placing in the Gadiformes, but they differ from the typical cods in that they possess one stout spine in the anterior dorsal fin.
The blackspotted grenadier or blackspot rattail, Lucigadus nigromaculatus, is a rattail, one of seven in the genus Lucigadus. It is found around southern Australia, New Zealand, and Chile, at depths of between 400 and 1,400 m. This species length is between 15 and 30 cm.
The slender unicorn rattail, Trachyrincus longirostris, is a rattail of the genus Trachyrincus, found in south-east Australia and New Zealand, at depths of between 850 and 1,300 m. Its length is between 30 and 60 cm.
Coelorinchus is a genus of rattails.
Coryphaenoides is a genus of rattails which is found in all oceans of the world. They are found in deep waters and C. yaquinae, recorded to 7,012 m (23,005 ft), is the only member in the family known from the hadal zone.
Gadomus is a genus of rattails in the family Bathygadidae.
Bathygadus is a genus of rattails of the family Bathygadidae.
Asthenomacrurus is a genus of rattails of the family Macrouridae.
Lucigadus is a genus of rattails.
Macrourus is a small benthopelagic genus of rattails from the family Macrouridae.
Nezumia is a genus of rattails.
Pseudocetonurus septifer is a species of rattail, the only known species in the genus Pseudocetonurus. This fish is found at depths of up to 950 m in the waters around Hawaii and in the south-eastern Pacific. It has recently also been recorded on the other side of the Pacific, near Taiwan, and this species probably has a pan-Pacific distribution but has been underrecorded due to the depths in which it lives.
Cetonurus is a genus of rattails.
Malacocephalus is a genus of rattails.
Mataeocephalus is a genus of rattails.
Sphagemacrurus is a genus of rattails.
Trachonurus is a genus of rattails.
Hymenogadus is a genus of rattails, marine fish.
