Ariidae L. S. Berg, 1958
* Froese, R. and D. Pauly. Editors. 2006. FishBase, version (02/2006). 
The Ariidae or ariid catfish are catfish that mainly live in marine waters with many freshwater and brackish water species. They are found worldwide in tropical to warm temperate zones.
Ariid catfish have sometimes been called crucifix catfish thanks to a rather peculiar skeleton that resembles a crucifixion.
The relationships of this family are not yet clear. By some sources, Doiichthys has previously been classified in its own family, Doiichthyidae. Two of the genera, Gogo and Ancharius, have been moved to a separate family called Anchariidae. Ariidae is divided into two subfamilies: Galeichthys is the only genus classified in the subfamily Galeichthyinae, while the rest of the genera are classified in the subfamily Ariinae.
Previously, Ariidae has been grouped in the superfamily Doradoidea, but then it was moved into Bagroidea (along with Austroglanididae, Claroteidae, Schilbeidae, Pangasiidae, Bagridae, and Pimelodidae. It has also been classified in a superfamily Arioidea containing Ariidae and Anchariidae.
Ariids are found worldwide in tropical to warm temperate zones. Ariids are unusual among catfish in that they live primarily in the sea; the majority of catfish families are strictly freshwater and have little tolerance for brackish or marine conditions. Ariid catfish are found in shallow temperate and tropical seas around the coastlines of North and South America, Africa, Asia, and Australia. They are absent from Europe and Antarctica.
Many species are also present in freshwater habitats; some species only occur in freshwater. In North and South America about 43 species extend into brackish water or are found exclusively in freshwater. Doiichthys is another freshwater species that is found in New Guinea.
Ariidae catfish have a deeply forked caudal fin. There are usually three pairs of barbels. They possess some bony plates on their head and near their dorsal fins. At least some species have venomous spines in their dorsal and pectoral fins.
Beyond their maritime habitat, ariid catfish have a number of unique adaptations that set them apart from other catfish. Most, if not all species, are mouthbrooding fish, with the male carrying a small clutch of a few dozen, golf-ball sized eggs for about two months until they eggs hatch and the fry become free-swimming.
One well known ariid catfish is the hardhead catfish, Ariopsis felis, abundant along the Western Atlantic coast from Massachusetts to Mexico. Although hardhead catfish reach a weight of about 5.5 kg and are good eating, they have a mixed reputation as game fish and are often considered nuisance bait stealers.
A less abundant species, more highly regarded as a game and food fish, is the Gafftopsail catfish, Bagre marinus. The range of the gafftop extends further south, to Venezuela.
The smaller ariid catfish have minor value as public and home aquarium fish. In 1972, the Shedd Aquarium in Chicago received worldwide acclaim for the first successful breeding of Ariopsis felis in captivity, a feat they have repeated several times since. The Colombian shark catfish Sciades seemanni (until recently Hexanematichthys seemanni) is a fairly popular aquarium fish, though it has been traded under a variety of spurious names, such as Arius jordani and Arius seemani. Less commonly traded aquarium species include Arius berneyi and Arius graeffei.
1. ^ The Crucifix Catfish by Allan James
Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License