Dominate Axolotl

I wasn't sure what to title this post. I have 2 female axolotls named Ebony and Ivory (wild and white with black eyes (too tired to remember the official names)). They have lived together since I got them last year with a partition till they were adults so they wouldn't munch on each other. They are always near each other and seem to always want to be together. Lately, Ebony seems to spend most of her time under a hiding place while Ivory stays outside. I am trying to figure out if Ebony feels threatened by Ivory or just likes hiding more than Ivory does. When I change the water they go to the opposite corner together and there doesn't appear to be any problem between them. Ebony often has a curved tail, but her gills don't come forward. They aren't competing for food. Should I be concerned or is this normal stuff? I had to move them downstairs for the summer because our upstairs is just too hot in the summer so they weren't where life happens like they are the rest of the year. They stayed in the same aquarium so it was the same habitat, just downstairs in the finished basement instead of in the living room upstairs. Any ideas would be appreciated.

I fail to see that you have any problem, some axolotls hide more than others.