Light is crucial to enhance the appearance of fish and supports the survival of living ornamental aquatic plants in aquariums. The light required by the fresh aquatic plants varies depending on the species. The light absorption by plants is most significant in the red (R, 640 nm) and blue (B, 464 nm) regions of the electromagnetic spectrum. The present study investigates the impact of different light colours, specifically white (as a control), blue, red, and green, on the growth of tissue cultures derived from Cryptocoryne elliptica plants cultivated under submerged conditions. The morphological traits and chlorophyll content of the plantlets were measured for ten weeks. Results showed that plantlets’ growth under blue light exhibited the longest petioles (4.9 ± 0.5 cm), leaf length (3.0 ± 0.2 cm), leaf width (1.3 ± 0.4 cm) and leaf number per plantlet (p < 0.05) compared with other treatments. The leaves of plantlets exposed to white light (control) exhibited the highest chlorophyll content, measuring 0.72 mg/g of its fresh weight. The number of newly produced shoot tips did not significantly differ between treatments (p > 0.05). This showed that in the current study, light source only alters the plant morphological traits, not the proliferation rate. In future studies, potential enhancements in the production of new plantlets can be explored through the investigation of various propagation methods, hormone treatments, and modifications to light intensity or duration.