“…The results of the present study indicated that juvenile Caspian roach were exposed to 24L and 18L:6D photoperiods had significantly better growth, WG and SGR than those exposed to 12L:12D, 6L:18D and 24D photoperiods. Similar results have been reported that growth performance could be enhanced by continuous light or extending the light photoperiod in Atlantic salmon juvenile, Salmo salar (Saunders and Harmon, 1990), red seabream juveniles, Pagrus major (Biswas et al, 2005(Biswas et al, , 2006. Also, the growth of sole, Solea solea (Fuchs, 1978), European seabass, Dicentrarchus labrax (Barahona-Fernandes, 1979), barramundi, Lates calcarifer (Barlow et al, 1995), olive flounder, Paralichthys olivaceus (Dou et al, 2003), black porgy, Mylio macrocephalus (Kiyono and Hirano, 1981), gilthead seabream, Sparus aurata (Tandler and Helps, 1985), rabbit fish, Siganus guttatus (Duray and Kohno, 1988) and snapper, Pagrus auratus (Fielder et al, 2002) larvae were better at 18 and 24 h light periods than at 12:12 h or shorter light periods.…”