Stress marks are when you start to see patterns on their bellies. Normally they have a whitish color than you will see something that looks like grey to black rings. Sometimes their backs & head will turn dark too. I hope this answers your question.
That's how I know mine is not happy. Especially when I take him outside of his viv to long or just outside.
thanks! do they come and go quickly? like if yours has been out of its tank too long how long would it take once you put it back in for them to go away?are they really obvious or quite subtle?
Mirage came out of brumation on April 26. He was doing great. On May 2 he started acting funny. We just redid his tank, and he keeps going into one of his hides. He just lays there. He shows no intrest in food. HELP!