Molly's strange bahavior. It is sick

[newhobbist]

My Black Molly don't look ok. It either sits on the bottom of the tank, which is very unusual for it, or swims in one spot moving very fast. It has been happening for last 2 days. Recently I've noticed that when it sits on the bottom, it's girlfriend (Lyretail Molly) sits at the bottom right next to it. What can it be?

 

[Toirtis]

One assumes that your water parameters and temperature are in order? Any other observations....unusual appearance to the fish, perhaps?