The differences in early life history traits among populations of grayling in Lake Lesjaskogvatn and surrounding lakes have been extensively studied the last decades. These populations are the offspring of a small group of grayling that migrated from the river Gudbrandsdalslågen over a century ago. However, the founder populations have never before been compared to the original population in Gudbrandsdalslågen. This study was a common garden experiment with different temperatures comparing the original population of Gudbrandsdalslågen with two newly-founded populations. The experiment had three different temperature treatments and followed the grayling from fertilization to after hatching. The traits studied were timing of eye development, timing of hatching, larvae growth rates and yolk sac consumption rates. Comparison of reaction norms for timing of eye development and hatching showed that there are genetic differences among the populations. The results for growth rate and yolk sac consumption rate were inconclusive due to lack of sample size in this part of the experiment.