Three hundred rainbow trout from each of two strains (Wytheville and the Soap Lake) were exposed in equal numbers to three non-overlapping wavebands of light (red, green, blue). One hundred fish from each strain were used as a control. These fish were exposed to unfiltered light of intensity equal to that of the three spectral treatments (21.4 lux). All fish were exposed to continuous light of the assigned experimental spectra for 53 days. Fish were fed trout chow twice daily at a rate previously found to maximize growth and efficiency. This feeding rate was determined by consulting hatchery records and the feeding charts developed by Haskell (1959). Mean length and mean weight of test animals may be affected by the rearing of individuals under specific wavebands of light (α = .001). Fish grown under blue or green light had the greatest mean length and fish grown under control or green light had the greatest mean weight while those reared under red light had the lowest mean length and mean weight. Although differences in coefficient of condition, yield, ferd conversion ratio, and survival were not Significant between light treatments (α = 0.05) in my study, significant differences may possibly be found in studies with a larger sample size. Although high variability and small sample size limit interpretation, this study suggests that certain light treatments used in conjunction with certain strains of fish could improve hatchery production. / Master of Science