Dictyosphaerium puichellum Wood, a typical a fresh water alga, is known for photosynthesis and expected to have photoluminescence also. We have, therefore, carried out a confocal fluorescence microscopic and spectroscopic study of this species. 3-D image constructed from 50 optical sections clearly reveals that fluorescence is originated from only the outer layer and not from the central core. Spectral investigation shows that a strong and sharp peak is located at 684 nm. At this peak value, the power measurement was carried out and the number of photons emitted by alga in the solid angle 48.59 f was calculated and found to be 3.4*1010/ sec. The other significant feature of the responsible fluorophore is that the present photoluminescence has a very low quenching rate and hence the emitted radiation is observed for a very long time (5 12 sec.). This directly suggests that this fluorophore could have direct applications in dye related industries.