I woke up this morning to find my black lyretail molly on the bottom of my tank. She looks healthy, shes laying on the ground upright moving her pectoral fins. Her gills are kind of panting though. Sometimes she will come up to the surface of the water, stay there for 2 or 3 seconds and swim right back down and just hit the gravel and lay there. What is wrong with her? She is usually swimming near the surface.