Laser light scattering characteristics of tropical fresh water diatoms and their siliceous frustules have been measured as a function of scattering angle at 543, 594 and 632nm wavelengths by using an indigenously designed and fabricated laboratory light scattering instrument in an attempt to carryout morphological characterization of the unique regular structures specific to these type of tropical fresh water diatoms. The instrument incorporates an array of 16 highly sensitive static Si detectors that measured scattered light signals from 10° to 170° in steps of 1°. A comparative analysis between the results obtained by using the three different incident wavelengths has shown that highest resolution is obtained at 543nm incident wavelength.