鲇形目（学名：Siluriformes），属鱼纲骨鳔总目，通称鲇鱼。世界七大洲，除南极洲之外，到处都有鲇鱼。有几种鲇鱼是海鱼。这类鱼大小差异极大，包括世界最大的淡水鱼──欧鲇，长达5米，重330千克，也包括一种很小的寄生鲇鱼，成体小于10毫米，是最小的脊椎动物。这个目包括35个科，但是现在分类表还在变动，大约有2855种，相当1/4的淡水鱼，1/10全部鱼纲的种类。

鲇形目除了电鲇科以外，其他种类在背鳍及胸鳍都有硬棘，有些含剧毒。

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).