Scleromystax is a genus of armoured catfish closely related to Corydoras, native to coastal river drainages of southeastern Brazil and adjacent Paraguay. Like their better-known relatives, Scleromystax species are small, bottom-dwelling scavengers plated in bony body armour rather than scales, using barbels to root through sand and leaf litter for food. The genus's defining feature is pronounced sexual dimorphism: mature males grow a dense "beard" of bristly odontodes across the cheeks and snout, along with noticeably longer fins, making the sexes far easier to tell apart than in most Corydoras.
This dimorphism has made Scleromystax a genuine hobby favourite, above all the bearded cory (S. barbatus) and the sailfin cory (S. macropterus), both long-established aquarium fish prized for striking, easily sexed males and a cool-tolerant, easy-going temperament. Breeding is correspondingly well documented among enthusiasts, with courtship display from bearded males a particular draw. The genus's conservation tally leans Least Concern where assessed, though more than half the atlas's eight species remain formally unevaluated.