I got a male guppy from petsmart the other day, and today I noticed he is not using his left fin. I didn't notice this when I picked him out, but I'm not saying it isn't possible that it was there. His fin just sort of sits there, not moving, and it and up around it on his body appears white. I tried to take photos but he would not cooperate, you couldn't really see it. Its just sort of "dead." But does look a little split. Does this sound like an injury or something else? If its not an injury, what sort of disease does it sound like? If it is an injury or disease, is there any chance of "saving" it? Any thoughts would be appreciated!