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.