The Aspredinidae are a small South American family of catfishes (order Siluriformes) also known as the banjo catfishes, with about 43 species. The common name of the family 'banjo catfishes' refers to their overall body shape, with a depressed head and slender caudal peduncle, that in some species gives the appearance of a banjo. Banjo catfishes lack an adipose fin. Most species lack the dorsal spine-locking mechanism. Though their bodies are scaleless, their skin is completely keratinized and is covered by large, unculiferous tubercles arranged in longitudinal rows; the entire outer layer of skin may be shed. Size ranges from less than 2.0 centimetres (.79 in) SL in Hoplomyzon papillatus to Aspredo aspredo at about 38 centimetres (15 in) SL, though most are less than 15 cm. Most species exhibit cryptic coloration. Aspredinids have a loss of alarm cells and the fright reaction that is present in other ostariophysans. (Source: Wikipedia.org, CC BY-SA)