Microscale Variation in Epidermal Thickness, Distribution, and Size of Mucus and Alarm Substance Cells in the Skin of Juvenile Fancy Carp (Cyprinus carpio)

Microanatomical analysis revealed that epidermal thickness, distribution, and size of mucus and alarm substance cells in the skin of juvenile fancy carp (Cyprinus carpio) is not uniform but varies in a regular pattern over the scales. The epidermis was uniformly thick over the projected borders of the scale but showed some variation including thinning and thickening in central areas. Mucus cells were abundant over the borders of the scale and in areas adjacent to preceding scales; they were fewer in a central area near the posterior border of the scale and in the pockets formed by the overlaying of scales. Mucus cells of areas adjacent to or under preceding scales had nearly twice the size of those from other areas. Alarm substance cells were concentrated in a central area toward the posterior border of the scale, virtually coinciding with the area with fewer mucus cells.