||This study investigates how the characteristics (spectrum and photoperiod) of artificial light affect European sea bass eggs and larvae from − 1 to 40 days post-hatching. Fertilised eggs and larvae were reared under five different light treatments: 12L:12D red light (LDR; half-peak bandwidth = 641â€“718 nm), 12L:12D blue light (LDB; half-peak bandwidth = 435â€“500 nm), 12L:12D broad-spectrum white light (LDW; 367 < λ < 1057 nm), 24L:0D broad-spectrum white light (LL) and 0L:24D (DD). The results showed that total length at day post-hatching 40 was significantly larger in larvae reared under LDB (15.4 Â± 0.6 mm) and LL (15.2 Â± 0.6 mm) than in larvae reared under LDR (11.7 Â± 0.7 mm). Overall wet weight was highest under LDB (21.6 Â± 2.02 mgr) and lowest in LDR larvae (13.6 Â± 1.48 mgr). Yolk sac and oil globule absorption occurred more slowly in LDR and DD larvae, while LDB larvae developed their fin, teeth and swim bladder significantly earlier than the rest of the groups. DD larvae were unable to capture food and mortality was 100% by day post-hatching 18, while LDR larvae did not feed on rotifers, but fed on Artemia from day post-hatching 16 onwards. The best survival was obtained with the LL treatment, although significantly more problems with swim bladder development and lower jaw malformations were also identified in this group. In summary, these results highlight the key role of the light spectrum and photoperiod for European sea bass larvae, the best performance being achieved under the light conditions that best approached those of their natural aquatic environment (LDB). These findings should be considered when designing rearing protocols for larvae in aquaculture.