Recent work in several fish species suggests that metabolic rate is a stable trait of an individual and that embryonic or juvenile metabolic rate is predictive of later growth. Intraspecific variation in metabolic rate is also evident. Since the body temperature of poikilotherms is determined by the environment, metabolic energy is directed to locomotion, somatic growth, and reproductive development. In embryonic rainbow trout, which exhibit minimal locomotion and have not yet begun reproductive development, standard metabolic rate can be a proxy measure for somatic growth potential. Utilizing an in vivo cell viability assay recently adapted to estimate metabolic rate, based on the reduction of resazurin to resorufin by intracellular Nadh2, or by using a traditional oxygen consumption assay, embryonic rainbow trout were sorted by metabolic rate. The highest and lowest quintile groups were then reared in a commercial trout hatchery under standard conditions to assess differences in juvenile and adult growth rates related to embryonic metabolic rate. Additionally, individuals assessed for high and low metabolic rate at first cleavage (12 hours post fertilization, 6 ATUs °C) or at 8 days post fertilizations (96 ATUs °C) were used in a bottom up proteomics screen in order to identify the genomic and proteomic drivers of embryonic metabolism. This work helps establish the rainbow trout egg proteome and gives insights into the genomic drivers of metabolic rate in early embryos. The identification of mechanisms during embryogenesis that predict future growth potential may ultimately allow identification of robust molecular markers of egg quality.