The marine microalgae, Isochrysis galbana is of fundamental importance to the aquaculture industry. In this study, I. galbana was cultured under blue, yellow LED and fluorescent light for 13 days, and the morphology, growth and proximate composition (protein, lipid and carbohydrate) were compared. Isochrysis galbana cultured under fluorescent light (8.19 × 106 cells ml−1) had higher cell density compared to blue LED (4.75 × 106 cells ml−1). The specific growth rate for fluorescent light (0.28 day−1) was higher compared to yellow (0.21 day−1) and blue LED (0.20 day−1) cultures. Lipid content was higher in I. galbana grown under yellow LED (27.94%, 0.19 g dry cell weight, DCW/L) compared to fluorescent light (23.01%, 0.15 g DCW/L). Whereas carbohydrate content was higher when grown under fluorescent light (7.99%, 0.05 g DCW/L) compared to blue LED (5.32%, 0.03 g DCW/L). The use of different colour LED can be used to enhance the proximate composition of microalgae.