Catfish are a fascinating and diverse group of fish which have become hugely popular as aquarium fish. They range from the tiny Otocinclus to giants like the Red-Tailed catfish. All catfish possess one or more pairs of barbels, one of their most distinguishing features. Catfish are also scaleless, and some are protected instead by 'armour' consisting of bony plates. The variety of size and form of catfish means there is a species to suit almost any aquarium setup.