Increasingly, studies are revealing that the environmental challenges experienced by an organism can not only have multiple effects on an individual level, but that these challenges may also impact unexposed offspring. Hypoxia is a physiological challenge that many aquatic organisms encounter in their environment, resulting in numerous physiological, phenotypic, and epigenetic changes. In this study, we use zebrafish (Danio rerio) as a model to investigate how paternal hypoxia experience impacts subsequent progeny. Males were exposed to moderate hypoxia (11-13 kPA) for 2 weeks, crossed to unexposed females to create an F1 generation, and progeny underwent an acute hypoxia (0-1 kPA) tolerance assay. Using time to loss of equilibrium as a measure of hypoxia resistance, we show that paternal exposure to hypoxia endow offspring with a greater tolerance to acute hypoxia, compared to offspring of unexposed males. In addition to phenotypic alternations, we also investigated changes in gene expression in offspring. We conducted RNA-Seq on whole F1 fry and detected 89 differentially expressed genes, including two hemoglobin genes and a selenoprotein that are upregulated more than 4-fold in offspring from male parents exposed to hypoxia. Paternal exposures to physiological challenges are thus able to impact the phenotype and gene expression of their unexposed progeny. We are now investigating whether changes in DNA methylation underpin the observed changes in phenotype and gene expression.