In this paper, we speculate about morphological characteristics of pithy granules in neutrophils from red seabream based on the results of analysis of optic phenomena found in the granules stained with peroxidase stain (diaminobenzidine method). This granules consist of two-layer core (inner core and outer core) and surrounding of the core (mantle). The wave length of incident brown light entered outer core through the PO-positive (brown) surrounding is resolved and change to white light. The light lighten inner core, and then ‘strong light’ radiate from inner core. This radiation lighten PO-positive surrounding (PPS). As the result, PO-positive reaction is not found in almost all part of the PPS. From the inner core, ‘weak light’ with fixed width, probably correspond to diameter of inner core, also radiate. Weak light don't mix with strong light. The PPS lighted by weak light show PO-positive and is recognized to spot under microscope.