Evaluation of selected metal nanoparticles on hatching and survival of larvae and fry of I ndian major carp, rohu ( L abeo rohita )

Different laboratory synthesized metal nanoparticles viz. Copper oxide ( CuO ), Zinc oxide ( ZnO ) and silver doped titanium dioxide ( Ag ‐ TiO 2 ) were studied for their effect on hatching and survival of larvae and fry of I ndian major carp, rohu, L abeo rohita both in direct application in tank water & coated onto tanks. Among these nanoparticles, CuO and ZnO nanoparticles exhibited highest percentage of hatching in both direct addition (78.0 ± 3.1% and 78.05 ± 4.2%, respectively) and coating onto tanks (58.6 ± 2.1% and 61.2 ± 2.7%, respectively) at 1 mg mL −1 while least percentage of hatching was recorded in Ag ‐ TiO 2 nanoparticles irrespective of its concentration & mode of supplementation. Highest survival of L . rohita fry (50.13 ± 2.2%) was observed after 15 days post hatching in CuO coated tanks followed by ZnO coated tanks (38.6 ± 2.8%) while least was recorded in Ag ‐ TiO 2 coated tanks (22.53 ± 3.0%). However in control tanks coated with Poly‐Urethane base with hardener and uncoated control tanks, the survival was 42.4 ± 1.2% and 41.36 ± 1.8% respectively. Further, significantly lower microbial load of water was recorded in CuO nanoparticles coated tanks (1.5 × 10 10  CFU L −1 ) as compared to uncoated control tanks (1.1 × 10 16  CFU L −1 ) without affecting water quality parameters. On the other hand, in Ag ‐ TiO 2 coated tanks, significantly lower microbial load (1.0 × 10 6  CFU L −1 ) as compared to uncoated control tanks at 15 days post hatching was recorded. However, Ag ‐ TiO 2 was toxic to L . rohita larvae & fry both in direct application and coating onto tanks. Considering the beneficial effects of CuO nanoparticle application, it has the scope of being used in a more eco‐friendly way in hatchery operations.