Catfish (or
catfishes;
order Siluriformes) are a diverse group of
ray-finned fish. Named for their prominent
barbels, which resemble a
cat's
whiskers, catfish range in size and behavior from the three largest species, the
Mekong giant catfish from Southeast Asia, the
wels catfish of Eurasia and the
Piraíba of South America, to
detritivores (species that eat dead material on the bottom), and even to a tiny
parasitic species commonly called the
candiru,
Vandellia cirrhosa. There are armour-plated types and there are also naked types, neither having scales. Despite their name, not all catfish have prominent barbel. 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. Many of the smaller species, particularly the genus
Corydoras, are important in the
aquarium hobby. Many catfish are
nocturnal, but others (many
Auchenipteridae) are
crepuscular or
diurnal (most
Loricariidae or Callichthyidae for example).
