"In catfish, gustation plays a primary role in the orientation and location of food".Because their barbels and chemoreception are more important in detecting food, the eyes on catfish are generally small.Many of the smaller species, particularly the genus Corydoras, are important in the aquarium hobby.Many catfish are nocturnal, Representatives of the genus Ictalurus have been introduced into European waters in the hope of obtaining a sporting and food resource.Flathead catfish, Pylodictis olivaris, is also a North American pest on Atlantic slope drainages.A flattened head allows for digging through the substrate as well as perhaps serving as a hydrofoil.As far as known for most catfish, features that are often characteristic of species such as mouth and fin positions, fin shapes, and barbel lengths show little difference between juveniles and adults.
All catfish, except members of Malapteruridae (electric catfish), possess a strong, hollow, bony leading spine-like ray on their dorsal and pectoral fins.
Members of the Siluriformes order are defined by features of the skull and swimbladder.
Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food.
Catfish also have a maxilla reduced to a support for barbels; this means that they are unable to protrude their mouths as other fish such as carp.
Catfish may have up to four pairs of barbels: nasal, maxillary (on each side of mouth), and two pairs of chin barbels, even though pairs of barbels may be absent depending on the species. Many larger catfish also have chemoreceptors across their entire bodies, which means they "taste" anything they touch and "smell" any chemicals in the water.