The olfactory system of European seabass (Dicentrarchus labrax L.,1758) is crucial sensory system. This is because fish generally live in mostly aquatic dim environment so depends typically on chemical sense potentiality, olfaction and gustation. The seabass’s olfactory system is built-up of two peripheral organs bearing multiple (38-40) lamellae arranged around median raphe acquiring a rosette shape. The two rosettes are stretched on the floor of the corresponding olfactory chamber and joining to the brain through the olfactory tract and bulb. The olfactory lamellae bear multiple sensory and nonsensory epithelial cells constituting the olfactory epithelium on the both sides of each lamella. But, since the fish live collectively in water, the later bearing the soluble odorant molecule must be continually renewed to be perfectly recognised.In the studied fish, Dicentrarchus labrax, the renewing water (ventilation) is performed mainly by two pair of accessory nasal sacs, lateral lacrimal and ethmoidal, extending from lateral sides of each olfactory chamber. There, the water flow or circulation is achieved and regulated actively by the compression of these nasal sacs found in-between bones of the skull and jaw apparatus. This mod of ventilation is categorised by Døving et al. (1977) as “cyclostomes” mod. Since, the kinocilia emitted from the flat terminal surface of its nonsensory sustentacular cells not copious and less developed, means that they are less used in ventilation “not Isosmates”