corydoras, any of numerous small South American catfishes of the genus Corydoras, family Callichthyidae, commonly kept as attractive scavengers in tropical aquariums. The species, identified by two rows of overlapping armour plates on each side, are hardy, unaggressive fishes commonly about 7.5 cm (3 inches) or less in length.
There are more than 100 species. Popular aquarium pets include: the bronze corydoras (C. aeneus), a common, metallic brown or green fish with a large dark patch on its body; the dwarf, or pygmy, corydoras (C. hastatus), an active, 4-centimetre-long species with a black band on each side; the leopard corydoras (C. julii), a silvery catfish patterned in black with stripes, short lines, and numerous small spots; and the peppered corydoras (C. paleatus), a pale, yellowish brown fish marked with dark spots and streaks.