Catfish may have up to four barbels: nasal ,maxillary (on each side of mouth), and two pairs of chin barbels , although pairs of barbels may be absent, depending on the species. Because their barbels  are more important in detecting food, the eyes on catfish are generally small. Like other ostariophysans , they are characterized by the presence of a Weberian apparatus . Their well-developed weberian apparatus and reduced gas bladder allow for improved hearing as well as sound production.
Catfish have no scale; their bodies are often naked. In some species ,the mucus-covered skin is used in cutaneous  respiration ,where the fish breathes though its skin . In some catfish, the skin is covered in bony plates called scutes ;some form of body armor appears in various ways within the order. In loricariods and in the Asian genus Sisor , the armor is primarily made up for one or more rows of free dermal plates. Similar plates are found in large specimens of lithodoras . These plates may be supported by vertebral processes , as in scoloplacids and   
in Sisor, but the processes never fuse to the plates or form any external armor By contrast in the subfamily Doumeinane (family Amphiliidae) and in hoplomyzontines (Aspredinidae), the armor is formed by expanded vertebral processes that form plates. Finally, the lateral armor of doradids , Sisor, and hoplomyzontines consists of hypertrophied lateral line ossicles with dorsal and ventral lamina. 

Catfish may have up to four barbels: nasal ,maxillary (on each side of mouth), and two pairs of chin barbels , although pairs of barbels may be absent, depending on the species. Because their barbels  are more important in detecting food, the eyes on catfish are generally small. Like other ostariophysans , they are characterized by the presence of a Weberian apparatus . Their well-developed weberian apparatus and reduced gas bladder allow for improved hearing as well as sound production.
Catfish have no scale; their bodies are often naked. In some species ,the mucus-covered skin is used in cutaneous  respiration ,where the fish breathes though its skin . In some catfish, the skin is covered in bony plates called scutes ;some form of body armor appears in various ways within the order. In loricariods and in the Asian genus Sisor , the armor is primarily made up for one or more rows of free dermal plates. Similar plates are found in large specimens of lithodoras . These plates may be supported by vertebral processes , as in scoloplacids and   
in Sisor, but the processes never fuse to the plates or form any external armor By contrast in the subfamily Doumeinane (family Amphiliidae) and in hoplomyzontines (Aspredinidae), the armor is formed by expanded vertebral processes that form plates. Finally, the lateral armor of doradids , Sisor, and hoplomyzontines consists of hypertrophied lateral line ossicles with dorsal and ventral lamina.