Do dalmation mollies sleep upside down?

I have two dalmation mollies. Alot of my fish were dying and one night my white and black looked like it was upside down in a tree. I umed it was dead, in the morning when I went to take it out it was swimming around. So I figured it was just my eyes playing tricks on me since the fish look upside down to me anyways. A few days later my black and white one was one the ground upside down inside the decorative tank skull. We thought it was stuck and used the back end of a wooden fork to gently scoot him out and he was fine. The next day he was again upside down on the ground and I used the fork again to scoot him and he swam away. Later I remembered reading that some fish sleep upside down, Are these fish just asleep and we're scaring the crap out of them with a fork as a wake-up call? Or is there something really wrong with them.... Both are fine right now