Electron Microscopic Studies on Helicoidal Architecture and Parabolic Pattern in Coloured Stripes of Hill-Stream Fish (Devario aequipinnatus) Skin

Scanning and Transmission Electron Microscopy of the coloured stripes on the skin of a hill stream fish, Devario aequipinnatus revealed the existence of patterns resembling parabola in certain regions. The oblique section of the coloured stripe showed a helicoidal arrangement of micrifibril bundles of some crystalline components, measuring about 0.27ìm in diameter and with spherical cross-sectional outline. The role of this parabolic pattern and helicoidal architecture (in coloured stripes of the skin) in reflecting circularly polarized light and its significance in biology of the fish is discussed with the help of relevant literature.