Molly not using one fin

[compudeity]

I have a silver molly who, suddenly, isn't using her right, front fin. She's not lethargic, and she's eating and swimming fine. The fin, however, is white at the base and where it connects to her body, her body looks slightly swollen. She seems ok in all other respects. She's using her left front fin with no problems and it looks normal.

Any ideas?

[bobrob]

Maybe she has been beat up a bit. What else is in the tank with her ?

[compudeity]

Well, it's a 55 gal tank and I have 3 mollies (including her, 2 fem and 1 male), 3 cories, 1 large old pleco, 1 marble angelfish (he/she tends to leave everyone alone), 4 zebra danios and 2 giant danios.