The axolotls take anywhere from about 14 to 20 days to hatch, on average. It all depends on water temperature. People say you can keep then in unheated water or up to 77F, I have a small heater in with mine and an airstone to circulate water around eggs, my water temp ranges from 64-68F. That temp is probably a perfect medium, I didn't want to leave eggs at room temp just because it's cold where I live right now and my adult axolotl tank stays at 60F now. I'm hoping they hatch around or before day 20, they have been doing quite a bit of movement especially in the mornings, it's exciting to watch.