A comparative study has been made of the mucogenic epidermis of the common carp,Cyprinus carpiovar.communis, and the three Indian major carps,Catla catla, Labeo rohitaandCirrhina mrigala: on the basis of epidermis structural organization, these species are easily differentiated.The epithelial cells in the superficial layer, as in most fishes, show secretory activity, evidenced by positive histochemical reactions, which is high inC. carpiovar.communis, moderate inC. catlaand low inL. rohitaandC. mrigala. The epithelial cells in the underlying two or three layers also give positive reactions, though their intensity is relatively weak.The mucous cells in C.carpiovar.communisare distributed in large numbers arranged in several superimposed layers in the outer regions of the epidermis, whereas inC. catlathey are fewer in number and are widely separated in the surface layers as well as in the deeper layers of the epidermis; in both species the mucous cells appear rounded, large, and open on the surface by wide pores. In contrast, inL. rohitaandC. mrigalathe mucous cells are smaller, restricted mainly to the superficial layer, close together in a single row, and open on the surface by narrow pores. The overall density of mucous cells inL. rohitaandC. mrigala, as inC. catla, is much lower than inC. carpiovar.communis.In the epidermis ofC. carpiovar.communisthere are a large number of mucous cells, and the few club cells are restricted to the deeper layers. In contrast, in the epidermis of the three Indian major carp the overall density of the mucous cells is much lower and the club cells are very numerous. It is suggested that the high density of club cells compensates an overall low density of mucous cells as an adaptation for an effective defence mechanism.Increased mucus production in the epidermis of C.carpiovar.communis, as evidenced by a large number of mucous cells in outer regions and high secretory activity of superficial layer epithelial cells, is associated with increased precipitation of mud held in suspension, needed as an adaptation to the species’peculiar bottom‐scooping habits.The varied density of the taste buds in the epidermis of the four carp is associated with their feeding hab