All propagation of rainbow trout ( Oncorhynchus mykiss) for the purpose of aquaculture utilizes in vitro fertilization following collection of gametes from the broodstock. Evidence indicates that there are unexplained differences in the fertility of female broodstock that affect early embryo survival. Our objective was to identify any effect of coelomic (ovarian) fluid during in vitro fertilization on embryo survival in egg batches from female rainbow trout that varied with respect to fertility . The experimental design involved dividing egg batches from individuals into two treatment groups (~ 200 eggs each). One group was washed with a buffered solution (modified Cortland's solution) to remove the coelomic fluid. The other group, as a control, remained unwashed. The eggs from the two treatment groups were fertilized in vitro with semen from the same male and subsequently incubated for 12 h. At 12 h, 25 eggs were randomly removed from each of the groups and scored based on the proportion of embryos attaining cleavage, indicating a viable embryo. Removing coelomic fluid from egg batches designated as originating from a sub-fertile female (< 80% embryo viability in the unwashed group) showed a consistent, statistically significant ( p < 0.05) increase in viability over 5 separate trials (30 females each).