Today I noticed my garter had laid a particularly smelly pile on the side of his cardboard tube. What stood out to me was, before I had taken the picture, (It dried, I assume) it left a considerable wet spot on the tube and the paper towel. Is a runny stool a sign of something bad? Or am I just overreacting?

It's eating frozen/thawed Tilapia and had a little bit of Black Sea Bass several weeks ago, if that's of any help.garterstool.jpg