Particular kind of epidermis, most markedly developed in Mormyridae. There are three layers. The base consists of moderately tall prismatic cells, followed by a few tiers of polyedric cells. The middle layer consists of extremely thin hexagonal cells, the platelet cells, 60 µm across, 0.22 µm thick. They are arranged in stacks or columns of several hundreds platelets each, the actual number depends on the size of the fish and varies with the region of the body. Diameter and thickness of the single cell, however, are independent of the species or genus. The distal or outer layer again consists of polyedric cells. There are no mucous cells within the electroreceptor epidermis and the normal epidermis of both Mormyridae and Gymnarchus. Around the sensory organs, electroreceptors as well as free neuromasts, a kind of lateral line organs, there are islets of normally shaped (polyedric) cells, arioles.
The arioles are leading the electric current trough the receptor cells, whereas the electroreceptor epidermis is a kind of shielding, because of its low capacitance the short pulses can not run across the platelet-layer and is forced through the arioles. The electroreceptor-epidermis is somewhat translucent in live animals, hence the head contour sometimes may look double, This is most often to be seen in Petrocephalus, where this kind of epidermis on the head is particularly thick. In preserved specimens is easily peels off with the effect that many museum fishes are void of this structure; may be the collectors mixed the epidermis up the a mucus layer as usually found in fishes and removed it before putting the fish into alcohol or the like. The peeling, on the other hand, has the advantage that the electroreceptors may be counted with ease, for they will stick to the epidermis and have the quality of staining metachromatically with toluidinblue. Type A gets greenish, type B reddish, knollenorgans dark purple. The free neuromasts of the lateral line usually will stick to the corium and do not accept the stain.

Alternative form for electroreceptor epidermis : platelet cells.