Now that I look at her again (She moved and is in a more relaxed position) I don't see it anymore.I suspect it was the rib I was seeing like you said. Thanks so much for your response because I was worried! ):
Also, I used to have another adf with this one but it unfortunately passed away.. I was thinking of maybe getting another small fish to keep in the tank since she seems really bored.... Do you know which type of fish are safe to keep with adf's?