Is this something I should be worried about?

[jeffp]

Noticed on one of my mollies today, a small white circle on her tailfin. Is this something I should be worried about or is it just nothing? The attached pictures are the best I can get right now

 

[Flossie]

How long has it been there? Is ur no1 and no2 at 0? It don't look threatening... But I
Would keep an eye on it