Optimum light wavelength and light intensity for rearing juvenile African Catfish (Clarias gariepinus)

The present study examines the optimum light wavelength and intensity for rearing African catfish (Clarias gariepinus) juveniles. For this purpose, African catfish juveniles (average total length: 26.0 ± 5.0 mm) were reared (20 fish/30 L) under five light colours (white, blue, green, yellow, and red) with three light intensities (1.40, 0.014, and 0.0014 μmoles/m²/s) in triplicate for 14 days. The survival rates and specific growth rates (SGRs) were then calculated. The results of the present study showed that the survival rates of African catfish juveniles were high under all light conditions with no significant differences among light wavelengths or light intensities (P < 0.05). These findings indicate that the survival rates of African catfish juveniles were unaffected either by light wavelengths or by light intensities. However, there were significant differences among light wavelengths for the SGRs, with yellow light resulting in the highest SGR. As for the effect of light intensities on fish growth rates, the results were insignificant. Thus, yellow light is recommended for rearing African catfish juveniles