Silurus is the type genus of family Siluridae, the Old World catfish, and it contains some of the largest freshwater fish in Eurasia. The atlas covers 2 species spanning an enormous size range - 51–107.5 in - native across a broad swath of Europe and Asia including Russia, China, and much of central and eastern Europe (Austria, Belarus, Bulgaria, the Czech Republic, Estonia, Finland, among others). Fish in this genus share the scaleless, elongate silurid body plan: a flattened head, a very long anal fin running most of the body's length, small eyes, and a wide mouth ringed with barbels used to hunt by touch and scent in low-visibility water.
The wels catfish (Silurus glanis) is the genus's best-known member and one of Europe's largest freshwater fish, a long-lived apex predator that anglers pursue specifically for its size rather than its rarity; the Amur catfish (S. asotus) is a smaller East Asian relative important in regional fisheries and aquaculture across its native and introduced range. Neither is a realistic home-aquarium fish given the adult size involved - Silurus belongs in public aquaria, large ornamental ponds, or the wild, not a home tank. Both atlas species carry a Least Concern IUCN assessment, consistent with wide native ranges and, for the wels catfish in particular, a long history of successful introduction well outside its original range.