Eurythermal temperate fish are able to survive over a wide range of water temperature ranging from near zero to over 30?C throughout the year, while maintaining their normal physiological and biochemical processes by temperature acclimation. Medaka Oryzias latipes is one of typical temperate eurythermal fish, which inhabit the above temperature range. To disclose the mechanisms involved in temperature acclimation of medaka, global gene expression analysis was carried out using next generation sequencing.