Not necessarily. They can really get "stress marks" for a lot of things. It could be anything from being cold and trying to warm up, to catching their reflection in the glass, wanting out of their viv, being scared or nervious, or just generally being in a bad mood lol. My female has never had stress marks with the exception of the two times she's been sick. First was parasites, second was some kind of infection. If you know you have everything set up correctly, they are being cared for properly, and they do not have any other indicators of illness I would not worry too much about stress marks. With Mem, my male, when he gets them on occasion I pick him up for snuggles and they go away, so I know he's just faking it. :lol: