Effect of nanosilver particles was studied on the hatchability of rainbow trout (Oncorhynchus mykiss) egg and survival of the produced larvae at about 12ºC. In the first experiment the water-based nanosilver particles was used at concentrations of 0.5, 1, 2 and 4 mgL^-1 for 30 minutes per day starting 24 hour post egg incubation until the hatching time. The mean percentage of hatchability reached in 27.6±0.2, 38.2±0.1, 41.6±0.4 and 48.6±1.5 in troughs treated with 0.5, 1, 2 and 4 mgL^-1 nanocid, respectively compared with 64.7±0.2 % for trough treated with malachite green at 2 mgL^-1 as positive control (P<0.05) and 5.1± 0.2 % for trough without treatment (untreated group) (P<0.0.5). In the second experiment the effect of the nanosilver particles was evaluated in the form of nanosilver dressing i.e. coating nanocid on the surface of the incubator troughs. The mean percentage of hatchability was 69.4±0.1% compared with 52.5%±0.1 recorded for normal control (trough without nanosilver dressing) (P<0.05). When growing the produced larvae in the same troughs until one g in body weight, there was an insignificant increase in the weight of larvae kept in nanosilver trough ( mean weight 1.12±0.09 g) compared to control group (mean weight 1.03±0.02g) (P>0.05). These data suggest a possible application of nanosilver particles in aquaculture sector particularly using incubator troughs of trout containing nanosilver materials.