The alfonsino (Beryx decadactylus), also known as the alfonsin, longfinned beryx, red bream, or imperador, is a species of deepwater berycid fish of the order Beryciformes. It can be found in temperate and subtropical ocean waters nearly worldwide, though it is uncommon. It is typically associated with deep-sea corals, and schools are known to form over seamounts. Adults are demersal and search for prey along the ocean floor, primarily fish, cephalopods, and crustaceans. Like other members of its family, it is remarkably long-lived, with individuals reaching ages of up to 69 years, and possibly longer. It can reach sizes of up to in length and in weight and is targeted by commercial fisheries. Its low reproductive rate and the time it takes for juveniles to mature make it vulnerable to expanding deep-sea fisheries, but it is listed as Least Concern by the International Union for Conservation of Nature (IUCN) due to its extensive range. Taxonomy and phylogeny The first scientific description of the alfonsino was authored in 1829 by Georges Cuvier in the third volume of his 22-volume ichthyology collection, Histoire Naturelle des Poissons, who gave it the name Beryx dodecadactylus. It was renamed B. decadactylus by ichthyologist G. E. Maul in 1990. The etymology of its generic name is unclear, but it likely comes from the Greek name for a fish, but which species it was originally used for remains unknown. It is possible that Beryx originally described a species of parrotfish, or did not describe a fish at all. Description The alfonsino has large eyes and a deep, compressed body, 1.9–2.5 times its standard length at the greatest depth. It is a rose red color dorsally and orange ventrally. The rest of its body is silvery-pink, and the breast is yellow-white in color. Fins and the inside of the mouth are bright red. The anal fin is distinctly larger than in many fish species and its caudal fin is deeply forked. Its bright red color is a common adaptation to deepwater surroundings, where red is filtered out of the light spectrum. Although the most common size is , it can reach lengths of up to TL. The maximum published weight for an alfonsino is . Juveniles have heavy head spines, while adults do not. Distribution and habitat The alfonsino is found worldwide in subtropical and temperate waters, with a latitudinal range extending from 70°N to 48°S. It is