Ok thank you. I can see the logic in that.I am not going to guess as to the spots; my experience with "disease" is extremely limited (fortunately) and others are better able to assess. But the parameters play into any "problem" because each species of freshwater fish has evolved to function in what really is a very specific environment, which obviously includes water parameters. Individual fish can respond differently to adverse conditions. Mollies must have a GH of 12 dH or higher, and a basic pH in the high 7's or higher. When this is lacking, they struggle tocarry out basic functions, and usually wear themselves out. The stress from this causes other issues that normally they would be able to handle.
Flashing can occur from parameter issues, from parasites, from ammonia/nitrite/nitrate issues...and clamped fins, lethargy, resting on the substrate the same. Before we even consider adding some sort of medication, fixing the obvious problems like the parameters is best.
The spots are just the algae on the glass. The fin is the only visible issue.
I am just so keen to fix it. I’ll make it a priority to find the parameters.
Thanks for taking the time to help.